1725, "the need very badly to urinate," from Latin micturitum, from past participle of micturire "to desire to urinate," desiderative of mingere "to urinate," from PIE root *meigh- "to urinate." As during the final 20 minutes of a 4-hour film after drinking a 32-ounce Mountain Dew from the snack bar and the movie ends with a drawn-out farewell scene while Frodo is standing on the pier and wavelets lap audibly on the dock the whole time as if the director was a sadist set on compounding your torment. Also used, incorrectly, for "act of urinating."
"urinate," by 1835, from micturition; malformed and with an erroneous sense; condemned from its birth.
Proto-Indo-European root meaning "to urinate."
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit mehati "urinates;" Avestan maezaiti "urinates;" Greek omeikhein "to urinate;" Latin mingere "to urinate;" Armenian mizem "urinate;" Lithuanian minžu, minžti "urinate;" Old English migan "to urinate," micga "urine," meox "dung, filth."