The breakeven point in economics is the point at which cost or expenses and income are equal - there is no net loss or gain, one has "broken even".
The point at which a firm or other economic entity breaks even is equal to its fixed costs divided by its contribution per unit output, which can be shown by the following formula: -
The break even point is also the point on a chart indicating the time when something has broken even, and is a general term for not having gained or lost something in a process.
Other uses of the term
In nuclear fusion research, the term breakeven refers to a fusion energy gain factor equal to unity.
The notion can also be found in more general phenomena, such as percolation, and is rather similar to the critical threshold.