Green’s Dictionary of Slang

boss n.3

[? boss-eye n., i.e. a ‘squint’ at]

a view, a sight of.

[UK] ‘’Arry on St. Swithin’ in Punch 4 Aug. 49/1: Couldn’t do a lark round with the ladies or git a fair boss at a race.
[UK] ‘’Arry in Venice’ in Punch 27 May 88/1: Whilst I’ve got a bob I’ve a chance for a boss at the Bride o’ the Sea.

In phrases