(informal) In good health. / (informal) In excellent or top condition. / (of a ship) First-class. (Compare A 2 and A 3, which are inferior grades.)

Under the International Union of Railways ("UIC") classification system, a steam locomotive that has two coupled driving wheels followed by two trailing wheels, with no leading wheels; also called an 0-2-2.

first rate or excellent / (of a ship) in first class condition

plural of A1

plural of A1/C

(military) Alternative form of A1C

(software engineering) Abbreviation of accessibility.

plural of A1C

(military) Abbreviation of airman 1st class. / (biochemistry) Abbreviation of glycated hemoglobin.

plural of A1A-A1A