Our only definite reference to an eket is during the Disaster of the Gladden Fields of III 2, so dating before or after that point is difficult. It was clearly an established part of a Dúnadan's weaponry at this time, so it was surely used in Númenor before the Exiles came to Middle-earth.

It is unclear how long the eket continued in use during the Third Age. We do have a handful of accounts from later in that Age of short swords (for example, Frodo found one in the barrow after being trapped by a wight) but there is no way to be sure whether these were specifically of the eket type. It is even conceivable that the 'daggers' given to the Hobbits by Tom Bombadil were actually ekets, and perhaps even Sting itself was a short blade of this kind.

The name eket comes from an Elvish root ekte- that literally meant 'spear', but was used more generally in words for pointed weapons, as well as other pointed objects such as thorns.