us
Pronunciation: /ʌs/
pronoun
- 1used by a speaker to refer to himself or herself and one or more other people as the object of a verb or preposition: let us know we asked him to come with us both of usCompare with we.
- used after the verb ‘to be’ and after ‘than’ or ‘as’: it’s us or them they are richer than us
- North American informal to or for ourselves: we got us some good hunting

Phrases
-
one of us
- a person recognized as an accepted member of a particular group, typically one that is exclusive in some way: you’ll never be one of us
-
us and them (or them and us)
- expressing a sense of division within a group of people: negotiations were hampered by an ‘us and them’ attitude between management and unions

Origin:
Old English ūs, accusative and dative of we, of Germanic origin; related to Dutch ons and German uns

Is it correct to say they are richer than us, or is it better to say they are richer than we (are)? See personal pronoun (usage) and than.