Onkian

From Memory Alpha, the free Star Trek reference.

An onkian is a temperature unit used within the Romulan Empire.

Twelve onkians are equivalent to a temperature on the cold side of the Celsius metric system. Admiral Alidar Jarok, after requesting political asylum on the USS Enterprise-D, ordered water with a temperature of twelve onkians from the replicator in his guest quarters. (TNG: "The Defector")