- To cause a liquid, typically milk, to separate into solid and liquid parts, typically as a result of souring or the addition of a substance such as rennet.
- To cause a liquid to become thick and lumpy, often as a result of being spoiled or sour.
- To cause something to become thick and lumpy.
Middle english: from old english cyrdelian "cause to curdle", from cyrdel "curd, cheese".
- The milk curdled when it was left out of the fridge.
- The milk was curdled and had to be thrown away.
- The mixture curdled and became difficult to work with.
- The batter curdled and ruined the cake.
- The cream curdled when it was added to the hot soup.