In speaking of the cook ovens I may say that it was there the word "yegg" originated. It has not yet been locked in the dictionary, but it has a place in our language and it's about time its derivation was settled once and for all. It is a corruption of "yekk", a word from one of the many dialects spoken in Chinatown, and it means beggar. When a hypo or beggar approached a Chinaman to ask for something to eat, he was greeted with the exclamation, "yekk man, yekk man."

The underworld is quick to seize upon strange words, and the bums and hypos in Chinatown were calling themselves yeggmen years before the term was taken out on the road and given currency by eastbound beggars. In no time it had a verb hung on it, and to yegg meant to beg.

The late William A. Pinkerton was responsible for its changed meaning. His business consisted largely of asking questions and necessarily he acquired much misinformation. A burglar with some humor fell into Pinkerton's hands and when asked who was breaking open the country "jugs" he whispered to the detective that it was the yeggs. Investigation convinced Pinkerton that there were a lot of men drifting about the country who called themselves yeggs. The word went into a series of magazine articles Pinkerton was writing at the time and was fastened upon the "box" men. Its meaning has since widened until now the term "yegg" includes all criminals whose work is "heavy".

Jack Black, You Can't Win, 1926.