I'll ignore doctrinal definitions, which often get caught up in detail and try too hard to link in with other related terms (thus you get a lovely collection of esoteric labels such as 'neutralise, destroy, suppress,' etc) that end up getting horribly misused.

A definition should also span all levels at which the activity van be conducted - in the case of a raid a section/squad through to a Corp can conduct it, so it should not be dependent on span of command or scale of execution.

With that in mind, I would define a raid as "an offensive operation that does not involve occupation".

You do something offensive and then you leave, in other words.