Quennar, surnamed Onótimo, was a Loremaster of Aman. He wrote extensively about the reckoning of time among the Valar. His great work the Yénonótië was cited by Rúmil in the Annals of Aman, particularly his writing explaining the length of the Valian year and its relation to the waxing and waning of the Two Trees. Quennar also calculated the duration of Valian years compared to Years of the Sun. Aside from his work on reckoning that Rúmil cited, almost nothing is known about Quennar's writings or his life in general.
Quennar's first name is a bit mysterious; the first part seems to incorporate the Quenya word for 'person', quen. The second part of his name might be related to nár, 'flame'. Onótimo means something like "Reckoner", originating from the verb onot- 'count up' and the masculine agental suffix -mo.