Key
An English and Manx surname that is usually treated as a form of Kay, though some Manx writers linked it to MacKay.
The #1,037 most common surname in the United States (2010 Census) — about 1 in every 9,216 Americans shares it.
Etymology
The surname Key is generally explained as a variant of Kay. In Lower’s dictionary it is given simply as “the same as Kay,” while Manx scholarship sometimes connected Key with an abbreviated form of MacKay. Because the name occurs in both English and Manx contexts, its exact origin may vary by family line.
History
Lower’s 19th-century work treats Key and Keyes as forms of Kay, and that remains the safest general explanation. In the Isle of Man, however, A. W. Moore and later writers noted that Key is especially common there and may reflect contraction from MacKay in some cases. The name is established in English-speaking records and later spread widely in Britain and the United States.
Origin
Regions
Variant spellings
Fun fact
Manx antiquarians once described Key as a distinctly Manx surname and even noted that it was more common than Kay in some local records.
From the historical record
“Jouru., p. 327. KEY. KEYES. keys. The same as Kay, which see. KEYMER. a parish in Sussex, KEYNES. See under Cheney. KEYNTON. Perhaps Keynston, a parish in co. Dorset. KEYSER. German, kaiser, an emperor, a Ca3sar. This name must be an importa-”
— Patronymica Britannica: a dictionary of the family names of the United Kingdom