genitive masculine/feminine/neuter singular of quī
köken: From the earlier quoius (the standard spelling until the early Empire), either from Proto-Italic *kʷojjos, from Proto-Indo-European *kʷosyo secondarily marked with the gen. sg. *-s, or from Proto-Indo-European *kʷo-s-yo-s, a thematic adjective like Ancient Greek ποῖος (poîos, “of what sort?”) and Oscan púiiu (“cuia”), púiieh (“cuius”). The latter is more likely, since if the adjectival use had…
Tītyre, sī toga calda tibi est, quō tegmine fāgī?Dīc mihi, Dāmoetā, 'cuium pecus' anne Latīnum?Nōn, vērum Aegōnis nostrī; sīc rūre locuntur.
Sustineō enim nōn modo meam, vērum etiam philosophiae dēfēnsiōnem, cuia magnitūdō vel minimam reprehēnsiōnem prō maximō crīmine aspernātur.