lookup n. (Computers) An operation that determines whether one or more of a set of items has a specified property; as, they wrote a program to do a table lookup.
... receptacle, a set of which might be used to apportion data items for sorting or lookup purposes. When you look up a name in the phone book (for example), you typically hash it by extracting its first letter; the hash buckets are the alphabetically ordered letter sections. This term is used as techspeak ... — The Jargon File, Version 4.0.0
...
