A keeping of records meant to outlast those who made them. An archive's discipline is that nothing is quietly removed.

A structured store built so things can be found again reliably. Its whole discipline is retrieval.

A container that slides out of a larger body to show what it holds. Closed by default, opened on purpose.

The frame that holds many in order — storage standing upright, everything visible.

An authoritative list kept so that entries can be relied on. A registry's worth is that someone maintains it.

That which waits to be asked and answers when it is. Named for serving — it does not act on its own.