A yahren is a Colonial measurement of time.
Analagous to an Earth year; plural form is same as singular, "yahren".
Note[edit]
Within some fan circles, a yahren is considered to be around two-thirds (2/3) the length of an Earth year, thus helping to explain the relative longevity of Colonial people compared to Terran humans.
In the reimagined series the colonials say year instead.
See also: Thousand Yahren War
See also: Units of Measure (TOS)