There is a house in Cherry street, not far from Catherine Market […]. A little to the north of its door stands an old-time tree; and for many a year it has been known to the “crossmen” and “knucks” of the town as “Jack Circle's watering place” and “fence.”
Source: wiktionary
A knuck in the front rank of a crowd desiring to steal a watch from the pocket of a gentleman standing on either side of him, first folds his arms across his breast; and pretending to be intensely looking at some object before him, stretches out the arm next his victim, […]
Source: wiktionary