Kates
Kates is most likely a variant of Kay or Kate, often a surname that began as a nickname or patronymic form.
The #7,284 most common surname in the United States (2010 Census) — about 1 in every 67,500 Americans shares it.
Etymology
The surname Kates is usually treated as a variant spelling connected to Kay and Kate rather than a single fixed source word. In English surname history, that can point to a nickname, a shortened pet form, or a patronymic formed from a personal name. The final -s may also suggest “son of” or simple dialectal spelling variation.
History
The historical evidence for Kates is thin in the excerpt provided, which only points the reader to Kay. In practice, surnames of this type often became fixed in England and later spread to North America through ordinary migration and record-keeping variation in spelling.
Origin
Regions
Variant spellings
Fun fact
The extra -s at the end of a surname often does not mean a modern plural at all; in older English records it could reflect pronunciation, family form, or scribal habit.
From the historical record
“Carsac in Perigord, Aquitaiue. Kates. Sre Catts. Kay, armorially identifiiid with X3ay and Gay. Kaye. See Kay.”
— The Norman People and their existing descendants in the British dominions and the United States