A 1

Adjective

1. Excellent, first class
2. First-class condition ship- (Inferior grades are indicated by A 2 and A 3). - original use in Lloyd's Registry

A 1 was first applied to persons and other things by Dickens in 1837 in Pickwick Papers:

'He must be a first-rater,' said Sam.

'A1,' replied Mr. Roker.