A masculine suffix and ending in male names (PE17/43, 141; WJ/400), probably related to the masculine ending or agental suffix ✶-on(do) (NM/353; Ety/KAL). It becomes -or when following an n (PE17/141).
Conceptual Development: N. -on was often use as a male suffix in the Noldorin of the 1930s and 40s. In Gnomish of the 1910s, it seems G. -os was another common male suffix in words such as G. ainos “(male) god” from neuter G. ain “god” (GL/18) and G. hethos “brother” from neuter G. heth “✱sibling” (GL/48-49), though masculine G. -(r)on was still more common in this early period.
-ndon, case-ending for "similative": wilwarindon "like a butterfly" (see wilwarin), laurendon "like gold" _(PE17:58) In the post-LotR period Tolkien decided to abandon this ending, apparently because it was to similar to the agental suffix -ndo (PE17:58)_, and it does not appear in the Plotz decension.