What is Lazy Loading?

Question

What is Lazy Loading?

[Edit after reading a few answers] Why do people use this term so often?

Say you just use a ASP/ADO recordset and load it with data or

Answer 1

Lazy loading: you don't waste your time (nor your memory) with stuff you might not need. Then when you need it, it takes longer, but that's fine.

Example from life: instead of actually learning that French phrasebook, you learn the phrases one at a time, as they're needed. When does this make sense? If you're only going to be in France for a short time (i.e., you won't need a lot of the phrases) or if you need to leave very soon. If you're there for two years and/or you have a long time to study, then it might be much more efficient to just learn the whole phrasebook up front (eager loading).

[Inspired by the Atom as taught in gang terms by Venus on WKRP.]