[bruce343434]

lambda, callback, function, closure, anonymous function, thunk

It's all pretty much the same.

I like "synchronous callback" because this tells you two things:

1. it's synchronous, no need to add memory barriers

2. it _is_ a callback, it is called after the fact.

[zelphirkalt]

Could also add "continuation" to the list perhaps, from continuation passing style (CPS). But that might not be a callback, as it never really goes back, but always goes forward.