From Longman Dictionary of Contemporary Englishspare tyreˌspare ˈtyre British English, spare tire American English noun [countable] 1 TTCan additional wheel with a tyre on it, that you keep in a car to use if another tyre gets damaged2 FATthe fat around someone’s waist – used humorously
Examples from the Corpus
spare tyre• Thank goodness for my spare tyre, I can afford to lose a bit of that.• If only he took as much exercise as I did he wouldn't have that spare tyre, I thought unsympathetically.• Their companion, in his 20s, had an old, noisy van with a smiling face logo on the spare tyre. 