'broad-muzzled' originates from English, specifically from the words 'broad' and 'muzzle', where 'broad' meant 'wide' and 'muzzle' meant 'snout'.

'broad' comes from Old English 'brād'; 'muzzle' comes from Middle English 'musel' (from Old French 'museau'), and the modern compound formed by combining these two words in English.

Initially, 'broad' and 'muzzle' separately carried meanings of 'wide' and 'snout'; over time the compound came to be used specifically to describe animals with a wide snout as an attributive adjective.