A dead heat happens when two or more competitors finish level for a position that decides a bet. Dead heat rules divide the stake by the number of tied competitors. Only that share is paid at the full odds, and the rest is lost. The result is a payout smaller than a normal win but larger than a loss. Rules can differ between markets and between operators, so the terms of the individual bet should be checked.
Example
A 10 unit bet at fractional odds of 5/1 wins in a two way dead heat. Half the stake, 5 units, is paid at 5/1 for a return of 30. The other 5 units are lost.