Late Middle English; earliest use found in Robert Mannyng (d. c1338), poet and historian. Partly from account + -er, and partly from Anglo-Norman acontur, acuntur, acountour accountant, auditor from aconter, acunter, acounter + -ur, -our.
Definition of accounter in US English:
accounter
nounəˈkaʊntə
A person who accounts, reckons, or calculates.
Origin
Late Middle English; earliest use found in Robert Mannyng (d. c1338), poet and historian. Partly from account + -er, and partly from Anglo-Norman acontur, acuntur, acountour accountant, auditor from aconter, acunter, acounter + -ur, -our.