Note: Do not rely on this information. It is very old.
A 1, a symbol used in nautical language to signify a vessel of the first class at Lloyd's; hence, figuratively, anything very excellent.
“If you would have light and heat, why then are you not more in the sunshine? If you would have more of that grace which flows from Christ, why are you not more with Christ for it?”
–Isaac Ambrose, Looking Unto Jesus