Daily fantasy sports has its own vocabulary — some borrowed from sports betting, some specific to DFS apps, some RunsLeft-specific. This glossary collects 40+ terms with plain-English definitions and links to longer-form articles where they exist.
Entries are grouped by category and ordered alphabetically within each category. Every entry has a deep-link anchor for cross-referencing from other articles. Where a term has a full article behind it, the entry is the short form. Where it has a RunsLeft-specific framing, both general and RunsLeft usage are called out.
DFS structure
Daily Fantasy Sports (DFS). A contest where you pick a small group of athletes for a single day's slate and win money if they outperform the market. Two main flavors: pick'em and salary-cap DFS. Full intro in our DFS guide.
Lock (contest lock). The moment a contest stops accepting new entries or edits — usually first pitch of the earliest game. After lock, you can't add picks, swap players, or change your stake.
Pick'em. A DFS format where you pick a small group of players and forecast their individual stat outcomes (over/under on each) instead of building a full salary-cap lineup. Full mechanics in our pick'em guide.
Salary-cap DFS. The traditional DFS format: each player has a salary, and you build a full lineup (2 pitchers + 8 position players in MLB) whose total stays under a cap. DraftKings DFS and FanDuel DFS are the main operators.
Slate. The set of games available for a given contest. Operators slice slates by start-time windows — main, early-only, late-only — varying by sport.
Contest formats
Cash game vs. GPP (guaranteed prize pool). Two contest shapes in salary-cap DFS. Cash games (head-to-head matches, 50/50s, double-ups) pay out the top ~50% of entries roughly evenly — lower variance, more wins per entry. GPPs are tournaments where top finishers split a large prize pool with steep payout curves — much higher variance, lottery-shaped outcomes.
Flex play. A pick'em format with partial payouts when most picks hit but one or two miss. Lower all-hit multipliers than power play, but a backstop against the slip dying on a single miss.
Head-to-head (H2H). A two-entry contest — your slip or lineup versus one other player's, winner takes the pool. Lowest-variance contest type at any operator.
Multiplier. The payout ratio on a winning pick'em slip — a "10x multiplier" on a $5 entry returns $50. Scales with slip size (more picks = higher multiplier) and entry type (power pays more than flex).
Power play / Standard slip. A pick'em format where all picks must hit for the slip to win. Highest pick'em multipliers — roughly 5x for 3-pick, 10x for 4-pick, 20x for 5-pick, with operator variation. One miss kills the entry.
Pricing, odds, and operator math
American odds. The U.S. sportsbook pricing convention. Negative numbers (-110, -125) tell you what you risk to win $100; positive (+150, +300) tell you what $100 returns if you win. Math in our sports betting vs. DFS guide.
Closing line value (CLV). The difference between the line you bet at and the final line just before game time. Consistently beating the closing line is the strongest signal that a sportsbook bettor has a real edge, since the closing line is the market's best estimate after all sharp money has moved it.
Demon pick. A PrizePicks projection set above the player's standard line — harder to hit, higher payout if it does. Math implications in our prop bets guide.
Goblin pick. A PrizePicks projection set below the standard line — easier to hit, lower payout. Counterpart to the demon.
Hold (operator hold). The percentage of contest entry fees (or sportsbook stakes) the operator keeps as profit. Distinct from operator rake — rake is the cut from peer-to-peer prize pools; hold is the broader effective margin. Typical ranges in our math behind DFS losses.
Implied probability. The probability of an outcome that an odds line implies. For -110: 110 / (110 + 100) = 52.4%. For -125: 125 / (125 + 100) = 55.6%. Sum the implied probabilities across both sides of a market and the amount over 100% is the book's vig.
Operator rake. The cut a DFS operator takes from contest entries as their service charge — analogous to a poker room's rake. On pick'em apps, built into payout multipliers; on salary-cap DFS, an explicit percentage of entry fees.
Over/under. The standard prop-bet structure: a stat line is set (e.g., Aaron Judge 1.5 hits), and you pick whether the player exceeds it or falls short. Standalone bets at sportsbooks (American odds) or slip legs on pick'em apps.
Parlay. A sportsbook ticket combining multiple bets — every leg must win. The DFS analog is a pick'em power slip. Pays larger multipliers than individual legs, but the math gets meaner: leg probabilities multiply and vig compounds across legs.
Same-game parlay (SGP). A parlay where all legs come from the same game — e.g., Judge over hits + Cole over strikeouts + Yankees win. Sportsbooks adjust the math for correlation between same-game legs.
Standard line. On a PrizePicks board, the default projection on a player — the centered line standard pick'em slips use. Demons and goblins sit on either side.
Vig / juice. The bookmaker's built-in margin on a sportsbook line. A standard -110/-110 market implies probabilities summing to ~105% — the ~5 percentage points above 100 is the vig. Player props carry wider vig. Math in our sports betting vs. DFS guide.
Player props
Anytime HR. A yes/no prop on whether a player will hit at least one home run tonight. Priced at long odds (typically +300 to +800) because home runs are rare. See the prop bets guide for context.
Hits prop. Over/under on a player's hits. Typical lines: 0.5, 1.5, or 2.5. The single most-bet MLB prop. Full list in our prop bets guide.
HRR (hits + runs + RBIs). A combo prop summing all three counting stats into one line. Common version is over 2.5 HRR. Smooths out the lineup-position noise that makes RBI and runs props individually noisier than hits or total bases. Staple of DFS pick'em boards.
Pitcher props. Props on a starting pitcher's stats: strikeouts, outs recorded, innings pitched, hits allowed, earned runs, walks. Strikeouts is highest-volume; others have their own quirks. A pitcher-props deep dive is coming in /learn.
Prop bet. Short for "proposition bet" — a wager on a specific outcome inside a game, separate from who wins. In baseball: player-level stats (hits, total bases, strikeouts, HRs, runs, RBIs). Full coverage in our prop bets guide.
Strikeouts (K) prop. A pitcher's strikeout over/under for the start. Lines run anywhere from 4.5 to 9.5 depending on matchup and expected length of the start. One of the highest-volume MLB props alongside hits.
Total bases prop. Over/under on a player's total bases: single = 1, double = 2, triple = 3, HR = 4. Captures contact and power in one line. Most common pick'em prop because it rewards quality of contact.
Strategy and math
Bankroll. The total money you've set aside for DFS entries. Sizing each entry as a small percentage so a normal cold streak doesn't wipe it out is foundational discipline. Walkthrough in our variance guide.
Break-even rate. The win rate you need to clear over time to neither make nor lose money on a given product, after factoring in the operator's rake or vig. Sportsbook -110 bets break even at ~52.4%. A 4-pick power slip at 10x payout breaks even at 10% slip probability (~56% per independent pick). A 6-pick power at 35x breaks even at ~2.9%. Derivations in our math behind DFS losses.
Correlation. The degree to which two outcomes move together rather than independently. Picks on two players in the same lineup are correlated — same starting pitcher, weather, umpire. Correlation amplifies both wins and losses on slips that contain it.
Edge. General DFS / sports-betting usage: any positive expected-value spot where your probability estimate differs from the market's by enough to be profitable after the operator's built-in margin. RunsLeft uses "edge" specifically for spots where our model's probability estimate exceeds the market-implied probability by enough to clear the operator's rake or vig — spots where the math is friendlier than the operator's default. See math behind DFS losses for how the structural math sets the threshold.
Expected value (EV). The average outcome of a bet over many trials, factoring in win probability and payout. Positive-EV wins over the long run; negative-EV loses. Most casual DFS plays land in negative-EV territory because rake/vig pushes break-even above 50%.
Kelly criterion. A formula for sizing bets based on edge size and current bankroll, designed to maximize long-run growth while avoiding ruin. Full-Kelly is theoretically optimal but high-variance; most practitioners use fractional Kelly (1/4 or 1/2). Dedicated piece coming in /learn.
Line shopping. Checking the same prop across multiple operators before betting, since the same projection often prices differently. Judge over 1.5 hits might be -120 at FanDuel and -115 at DraftKings — the gap compounds across hundreds of bets.
Stacking. A salary-cap DFS strategy where you intentionally pick multiple players from the same team or game to take advantage of correlation. High-variance: big cashes when the stack hits, complete busts when it doesn't.
Variance. The gap between what's likely to happen on average and what actually happens on any given night, slip, or month. Single-game outcomes are noisy by definition, so even a player with a real positive edge has multi-week losing stretches. Full treatment in our variance guide.
Decisions and player management
Lineup spot. Where a hitter bats in tonight's order (1 through 9). Affects expected plate appearances, RBI opportunities, and runs scored. RunsLeft projections factor in the posted lineup spot for every hitter prop.
Park factor. A 100-centered multiplier describing how much a stadium inflates or suppresses a stat relative to neutral. 105 boosts ~5%, 95 cuts ~5%. RunsLeft uses three-year-averaged park factors in pitching projections — details on the methodology page.
Platoon split. A player's performance gap by opposing pitcher handedness. Some lefty hitters crush RHP but struggle vs. LHP. Lineup spots, prop projections, and manager rest decisions all factor in tonight's opposing hand.
Pull pattern. A starting pitcher's historical pitch-count distribution before being pulled by his current manager. RunsLeft surfaces this on /dfs/edges when the manager's sample with the starter is adequate (≥5 starts) AND the pattern is notable in either direction: an aggressive early-puller (averages under 78 pitches), a patient late-puller (averages over 92), or heavy-use (more than half of starts go over 100 pitches). Example context: "Hinch averages 102 pitches before pulling Skubal (12 starts, 9 over 100); CWS 24.1% K-rate vs LHP." Methodology details on the methodology page.
Quality flag. A transparency label RunsLeft attaches to projections that are less reliable for specific reasons. Three flags surface on /dfs/edges: Low expected PA (bench/utility player — model assumes full role usage, projection less reliable than for everyday starters), Small sample (limited 2026 MLB sample — projection weighted heavily on prior seasons and minor-league data), and Recent role change (recent trade or role change — manager-tendency context may be incomplete; this flag is defined but not yet fully fired in production, pending data-infrastructure work). Flags are transparency, not filters: the projection still renders unless you opt in to hide flagged rows.
Recent form. A short-horizon view of how a player has performed in their most recent at-bats or starts. Industry use is broad — anything from "last 10 games" to "last 30 days." RunsLeft surfaces recent form as a context block on /dfs/edges when a player's last-14-games rate diverges meaningfully from their season-long rate. The direction is called out as reinforces (recent trend agrees with the model's edge direction) or contradicts (recent trend disagrees) — both surfaced transparently rather than only the supportive cases.
Where RunsLeft fits
This glossary is a reference, not a sales pitch. Where we do something specific with a term — surfacing pull patterns, flagging projection quality, calling out recent-form contradictions — we've noted the RunsLeft framing in the entry. The model itself is at our tonight's DFS edges page, with per-player edges, context blocks, and quality flags rendered live.
Where to go from here
For deeper coverage: DFS intro, math behind DFS losses, variance deep-dive, pick'em comparison — plus more in /learn.