- a tire used or kept available as an emergency replacement on a vehicle.
- Informal. excess fat around the waistline.
Origin of spare tire
Idioms and Phrases with spare tire
Fat around one's middle, as in He's determined to lose ten pounds and that spare tire he's acquired. This expression transfers the term for an extra tire carried in cars in case of a flat tire to excess fat around the waist. [Colloquial; mid-1900s]