A prefix of Chinese origin used with a shortened form of given names to express familiarity, roughly equivalent to a nickname.
Ah Ming moved out of Chinatown last year.
1893 July 4, “Chinese Work in British Columbia”, inMissionary Leaflet, volume 9, number10,page 2:
I was called, at about an hour's notice, to takeAh Quai (the girl rescued in the spring), and go with Mr. Gardiner to Seattle, and give evidence in the case of one of the women brought over on the same ship withAh Quai.