Plural of hubcap; decorative metal or plastic covers that fit over the center of a vehicle's wheel to protect the axle and look stylish.
From hub (the center of a wheel, from Old English 'hufe') plus cap (a covering), a compound word that emerged once automobiles became common in the early 1900s.
Hubcaps are one of the most stolen car parts in history because they're valuable but loosely attached—thieves in the 1980s-90s would steal them to sell for scrap metal, leading to funny anti-theft designs including ones that popped off if someone tried to pry them.
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