Pronunciation: (ā' wun'), [key]
1. noting a vessel regarded by a shipping-classification society as being equipped to the highest standard and with equipment maintained in first-class condition.
2. Also,A number one. Informal.first-class; excellent; superior: The meals there are A one. Also,A-one,A 1,A-1
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.