thunk

Not surprisingly, a thunk is more expensive to store than a single number, and the more complex the thunked expression, the more space it needs. For something cheap such as arithmetic, thunking an expression is more computationally expensive than calculating it immediately.

This efficiency is offset by the fact that some of the calls made by Win32 apps must now be thunked down to 16 bits, something that isn't necessary in Windows NT and OS/2.