thumb
n. countablen. the short, thick finger on the side of your hand. It helps you hold things and use your phone easily.
n. the first digit of the human hand, set apart from the other four and opposable to them.
He gave a quick thumbs-up to show he was ready.
She scrolled through the news on her phone using only her thumb while holding a coffee cup.
The evolution of the opposable thumb is frequently cited as a primary factor in the development of complex tool use among early hominids.
Derived from Middle English thombe, thoume, thoumbe (“thumb”), from Old English þūma (“thumb”), from Proto-West Germanic þūmō (“thumb”), from Proto-Germanic þūmô (“thumb”), from Proto-Indo-European *tūm- (“to grow”). Cognate with West Frisian tomme (“thumb”), Dutch duim (“thumb”), Low German Duum (“thumb”), German Daumen (“thumb”), Danish and Norwegian tomme (“inch”), Norn tum (“thumb”), Swedish tumme (“thumb”), tum (“inch”), Ancient Greek τύμβος (túmbos, “burial mound”). Also compare Welsh tyfu (“to grow”), Latin tumēre (“to swell”), Lithuanian tumėti (“to thicken, clot”), Avestan 𐬀𐬨𐬏𐬙 (amūt, “strong”), Sanskrit तुम्र (túmra, “strong, thick”). The parasitic ‐b has existed since the late 13th century. Doublet of tomb.