Green’s Dictionary of Slang

york n.

[york v.]

a stare, a glance.

[Aus]Vaux Vocab. of the Flash Lang. in McLachlan (1964) 280: york a look, or observation; a flash-cove observing another person (a flat) who appears to notice or scrutinize him, his proceedings, or the company he is with, will say to his palls, That cove is yorking as strong as a horse, or, There is York-street concerned.