Meaning

noun an extra component of a machine or other apparatus

noun an extra car wheel and tire for a four-wheel vehicle

noun a score in tenpins; knocking down all ten after rolling two balls

originFrom Middle English spare, spar, from Old English spær (“sparing, scant”), from Proto-Germanic *sparaz, from Proto-Indo-European *sph₁rós, from the root *speh₁-. Compare Dutch spaar(zaam), German spar(sam) and spär(lich), Swedish spar(sam), Icelandic sparr (“sparing”); also Latin (pro)sperus (“lucky”), Old Church Slavonic споръ (sporŭ, “plentiful”), Albanian shperr (“earn money”), Persian سپار…

Etymology from Wiktionary, CC BY-SA 3.0