tumescence

noun

Etymology: First attested 1725, from French tumescence, from Latin tumescēns (“swelling”), present participle of tumēscō (“to begin to swell”), from tumeō (“to swell”) + -ēscō (incohative suffix) (English -esce, in this form -escence), stem from Proto-Indo-European *tum-éh₁- (“to be swelling”), stative stem of *tum- (“to swell”).

1. A swelling due to the presence of fluid.

   “It is still more remarkable that the reeves also, even in the presence of the males, will court each other and have intercourse. We may associate this with the high erotic development of birds, the difficulty with which tumescence seems to occur in them, and their long courtships.”

2. A swollen bodily organ; used especially of erectile tissue.