Definition:
A data item that is an aggregate of other data items of the same type that have something in common. Averages and distributions can be determined for data sets.
Editor note:
2009/10/23 Alan Ruttenberg. The intention is that this term represent collections of like data. So this isn't for, e.g. the whole contents of a cel file, which includes parameters, metadata etc. This is more like java arrays of a certain rather specific type
Editor note:
2014-05-05: Data sets are aggregates and thus must include two or more data items. We have chosen not to add logical axioms to make this restriction.