"the art of the accountant," 1848, from accountant + abstract noun suffix -cy. Accountantship is attested by 1818.
Entries linking to accountancy
accountant n.
mid-15c., "accounting officer, one who renders accounts," from Old French acontant (Modern French accomptant), from present participle of aconter "to count, enumerate" (see account (v.)). The sense of "professional maker of accounts" is recorded from 1530s. The word also was an adjective in Middle English, "accountable; liable to render accounts" (early 15c.).
-cy
abstract noun suffix of quality or rank, from Latin -cia, -tia, from Greek -kia, -tia, from abstract ending -ia (see -ia) + stem ending -c- or -t-. The native correspondents are -ship, -hood.