From wisdom + tooth, calque of Latin dēns sapientiae, which is itself a calque of Ancient Greek σωφρονιστῆρες (sōphronistêres, “prudent or self-controlled ones (i.e. teeth)”), because they arrive approximately when one has reached the age of prudence or wisdom. Compare also German Weisheitszahn (“wisdom tooth”), Danish visdomstand (“wisdom tooth”), Swedish visdomstand (“wisdom tooth”), Icelandic vísdómstönn (“wisdom tooth”), Dutch verstandskies (“wisdom tooth”, literally “intellect molar”), German Low German Verstandskuus (“wisdom tooth”, literally “wisdom molar”). Even Chinese 智齒, Russian зуб мудрости (zub mudrosti), Hebrew שן בינה, and Finnish viisaudenhammas mean "tooth of wisdom".
- (dentistry) One of the four (one upper and one lower on each side) rearmost molars in humans, which typically develop between ages 18-24.