"writing implement," late 13c., from Old French pene "quill pen; feather" (12c.) and directly from Latin penna "a feather, plume," in plural "a wing," in Late Latin, "a pen for writing," from Old Latin petna, pesna, from PIE *pet-na-, suffixed form of root *pet- "to rush; to fly."
Latin penna and pinna "a feather, plume;" in plural "a wing;" also "a pinnacle; battlement" (see pin (n.)) are treated as identical in Watkins, etc., but regarded as separate (but confused) Latin words by Tucker and others, who derive pinna from PIE *spei- "sharp point" (see spike (n.1)) and see the "feather/wing" sense as secondary.
In later French, this word means only "long feather of a bird," while the equivalent of English plume is used for "writing implement," the senses of the two words thus are reversed from the situation in English. Pen-and-ink (adj.) is attested from 1670s. Pen name is recorded from mid-19c.