Tomed

From Memory Alpha, the free Star Trek reference.

Tomed is the designation for an unspecified astronomical feature near the Federation-Romulan border not far from Vulcan space.

Sometime during the first half of the 22nd century, the Vulcan High Command led a mission to Tomed, which T'Pol was part of. (ENT: "Kir'Shara")

In 2311, the Tomed Incident between the Federation and the Romulan Star Empire led to numerous casualties on both sides and marked the beginning of the Romulan isolation over the following 53 years. (TNG: "The Neutral Zone")

It has never been clarified what the name "Tomed" exactly stands for. We might assume it is the designation for either a nebula, planet, star or star system.

Pocket TOS novel "Serpents Among the Ruins" describes the Tomed Incident dealing with a Romulan battle cruiser named Tomed, which again raises the likelihood of "Tomed" being a place name or some other type of proper noun which the ship was named after.

The novel "The Return" has a Romulan warbird named "Avatar of Tomed".