a 1

Preserved but no longer current.

Meaning · English

First-rate, the very best; "she’s a prime girl, she is; she is A 1."—Sam Slick. The highest classification of ships at Lloyd’s; common term in the United States; also at Liverpool and other English seaports. Another, even more intensitive form is "first-class, letter A, No. 1." Some people choose to say A I, for no reason, however, beyond that of being different from others.

Era: ca. 1874 (Victorian)

Where it’s used: Origin British & Irish English
Sources & notes

Historical definition reproduced from Hotten’s The Slang Dictionary (1874, public domain; Project Gutenberg #42108, retrieved 2026-07-31). Reflects the attitudes of its era.

Common questions

What does “a 1” mean?

First-rate, the very best; "she’s a prime girl, she is; she is A 1."—Sam Slick. The highest classification of ships at Lloyd’s; common term in the United States; also at Liverpool and other English seaports. Another, even more intensitive form is "first-class, letter A, No. 1." Some people choose to say A I, for no reason, however, beyond that of being different from others.

Is “a 1” formal or informal?

No register label has been reviewed yet — treat it as neutral and check the usage notes above.