What is "spumescent"

Spumescent \Spu*mes"cent\ (-sent), a. [L. spumescens, p. pr. of spumescere to grow foamy, from spuma foam.] Resembling froth or foam; foaming.

"foaming, frothing," 1856, from Latin spumescentem (nominative spumescens), present participle of spumescere "grow frothy," from spuma (see spume) + inchoative suffix -escere.

a. (context rare English) Resembling froth or foam; foaming.