To nail with a tack (small nail with a flat head).
To sew/stich with a tack (loose seam used to temporarily fasten pieces of cloth).
To maneuver a sailing vessel so that its bow turns through the wind, i.e. the wind changes from one side of the vessel to the other.
To add something as an extra item.
Often paired with "up", to place the tack on a horse.
An inverted state: a state in which something has been turned (properly) upside down or inside out or backwards.
The result of an inversion, particularly:
A second element which negates a first; in a binary operation, the element for which the binary operation—when applied to both it and an initially given element—yields the operation's identity element, specifically:
A morphism which is both a left inverse and a right inverse.
The winning of the coup in a game of rouge et noir by a card of a color different from that first dealt; the area of the table reserved for bets upon such an outcome.
(Kiowa-Tanoan) A grammatical number marking that indicates the opposite grammatical number (or numbers) of the default number specification of noun class.




