Glossary of Betting Terminology - from board cleaners to steam chasers to handle and hold

There are a few words and terms for betting and different types of bets that you might not have heard of, especially now that the gambling scene is booming in America, and on social platforms there are plenty of new buzzwords out there. Here are a list of some of the more advanced or important terms and concepts in sports betting:

Money line - essentially a straight market on 2 sides to win

Point spread  -  bet on the margin of victory in a game (like a handicap EU)

Reverse line movement  - when the line moves away from the side receiving the most volume, usually instigated by a big 'sharp' bet

Chalk - the favourites

Dutching - backing more than 1 selection in a market to give you the same return on total outlay

Arbing - backing both sides of the bet pregame to guarantee equal profit when different books or exchanges are offering different prices

Middling -  betting both sides at different lines following moves (points spreads) with a chance of winning both

Line - odds or point spread

Kelly - a staking formula or plan used to optimise EV  / edge

Originator - an odds compiler or handicapper who frames their own tissues

Juice/Vig - bookmaker's commission

Hold - bookmaker's margin in the market (overround)

Handle  - turnover in the market

EV - expected value, the amount you can expect to make on average making may bets with same criteria

Key number - the most likely numbers a game will be won by: eg 1,2 or 3, in football or 3 or 5 (pts) in Rugby

Averaging In - investing more when the market goes against you to lessen the average price of investment

Overround - the combined margin added to all selections in a market by the bookmaker to produce the vig

Underround - when the book %s add up to less than 100%. The mathematical edge is now in the punters favour

Bookie Margin - % added to the book to protect the bookmaker and bring in profits. The more confident the traders are in their prices the less the overround can be. Markets with lots of runners will see a bigger margin. Ie: Golf outrights: circa 55-60%

Tissue: a draft of the fair odds (usually to 100%) in a market. Sharp punters originate tissues to compare them against market prices and look for value

Machine - exchange

Ticket - betslip

Tout - tipster

Prop - subsidiary/specials market such as a player to score a header in football. These markets usually have a large margin and are much easier to beat despite said margin

Derivative - a market formed from a main market using derivative prices. (IE top 20 market in golf derived from outright prices

Steam chasing - when a line starts moving accross the board,  steam chasers will note it and get on board without necessarily knowing why it's moving

Top Down - an approach similar to steam chasing using methods that don't involve originating or handicapping to find an edge

Bottom up - compiling your own odds tissues using rankings etc and comparing them to market prices to hunt for value - the real sharps

Handicapping - originating odds using key variables, stats and weightings to form and quantify your opinion

Modelling - using an algorithm inputting data to churn out prices and probabilities

Parlay - multiple

Round Robin - series of parlays like in a yankee

Board cleaners - hoovering up stale prices by shopping around the books

Diversify -  broaden your portfolio of investments to manage risk and lessen variance

Closing line - the odds at the start of the game

Closing line value (CLV) - how much edge you realised according to the closing line vs odds obtained. In theory it should equal your EV but it doesn't necessarily as closing line and market efficiency theory is flawed like anything using averages.

Pickem  - 50:50, usually both sides at ~1.90

Bayesian - subjective, empirical, conditional probability

Small data - small sample sizes