tack
A small nail with a flat head.
Other meanings
A loose seam used to temporarily fasten pieces of cloth.
The lower corner on the leading edge of a sail relative to the direction of the wind.
Word history
From Middle English "tak".
Where this comes from
This definition is adapted from “tack” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.