A Quenya word deriving from an ancient form roko-kwén, 'horse-person', that was originally used by the Elves simply to refer to a person who rode a horse. The -quen ending could be either masculine or feminine; it implied no more than the fact that the person in question was a regular rider of a horse, especially as part of their profession.

Over time, especially among the Dúnedain, the word roquen took on a more specifically military meaning. Among the armies of the Númenóreans, at least in the later Second Age, it came to signify a particular rank, translated 'knight', that was above the common foot-soldiers who held the rank of ohtar. Given the origins of the word, the clear implication is that those who held the rank of roquen or knight typically formed the Númenórean cavalry.¹