[Old French -at or Latin -atus, -ata, -atum.]
One sense, usually derived from Latin originals, is that of an office, rank or position: doctorate, episcopate, baccalaureate (a university bachelor's degree). Others refer to place: a consulate is the place where the function of consul is carried out; a protectorate is a state protected or controlled by another. Some signify the office or territory of a ruler: sultanate, caliphate, vizierate.
The suffix can mark a group or collective body: electorate, mandarinate (often used for a group of powerful civil servants), rabbinate, senate, syndicate, triumvirate. Others describe a person who exercises some function: magistrate, advocate, candidate, curate, subordinate. A mandate, an official order or commission to do something, is from Latin mandatum, something commanded.
The suffix also indicates salts of acids whose names end in -ic, such as nitrate (a salt of nitric acid), carbonate (from carbonic acid), or acetate (from acetic acid). Compare -ite1. The related term hydrate refers to compounds containing chemically bound water. Several examples indicate the result of some chemical process: filtrate, precipitate, condensate, distillate.