From Longman Dictionary of Contemporary Englishnosebagnose‧bag /ˈnəʊzbæɡ $ ˈnoʊz-/ noun [countable] British English DSHa bag that holds food and is hung around a horse’s head
Examples from the Corpus
nosebag• It was currently enjoying a nosebag.• Offered a free bed and nosebag, Tony is there like a rat up a drainpipe.• Especially when the nosebag held a pale blue Ceylon sapphire and two adequately flaw-free white diamonds set in eighteen-carat yellow gold. 