Dosh is the fictional currency of Killing Floor 2, replacing the British Pound uses in prior games. While reference is made to Dosh throughout the original game, it does not appear as its own form of currency; it is only used as a casual or slang reference.
In Killing Floor 2, Dosh has received its own unique monetary symbol but otherwise functions identically to how the currency worked in the original game.
Dosh is received after killing enemies and at the end of a wave. The amount of Dosh earned for killing enemies is relative to the amount of damage done to the enemy. The amount earned at the end of a wave depends on the total Dosh earned by all players. Dosh can then be used to purchase weapons, ammunition, body armor, and grenades at the active trader station between waves.
The Dosh Vault is a feature in Killing Floor 2 allowing players to visually accrue a second form of Dosh (Vault Dosh or "Vosh") onto large palates in a warehouse by completing Daily and Weekly Challenges.
As stated in Mr. Foster's bio on the official Killing Floor 2 website, his birth sign (zodiac symbol) is Dosh.