An extremely small unit to measure things by, subdivided into a `gnat's dick-end´, (about 8 to the gnat's dick), and a `gnat's cock-hair´, (about 12 to the gnat's dick-end) thus giving an imperial scale of 96 divisions. This sort of accuracy is essential if you're trying to get people on the moon, and maybe one day we will!
Hebden Bridge council worker to oppo,who's struggling to put up a lamp post:
'Move bugger a gnat's dick toward canal'
Oppo gives a shove the wrong way.
'Aye lad, another gnat's cock-hair and yer reet.'