The term 2:1, E.G. is a RATIO which means that for every two of one thing, there is one of something else. The crossword solutions for this term are 'ODDS' (4 letters) and 'RATIO' (5 letters). ODDS are a type of RATIO which is used to describe the likelihood of an event occurring. It is usually expressed as a fraction or a decimal. For example, if the ODDS of winning a game are 2:1, then for every two losses, there will be one win. Ratios are mathematical expressions which compare two or more values. They are often used to compare the relative sizes of two or more quantities.