"moist or accompanied with moisture; containing, or formed or effected by, water or vapor; wet, damp," early 15c., from Old French humide, umide "damp, wet" (15c.) or directly from Latin humidus "moist, wet," variant (probably by influence of humus "earth") of umidus, from umere "be moist, be wet," from Proto-Italic *umo- "wet" (also source of Latin umidus "wet, moist," umiditas "moisture," umor "moisture, fluid," umectus "moist, wet"), perhaps from PIE *uhrmo- "wet," from the same source as Latin urina [de Vaan].
"spittoon," 1779, a colonial word, from Portuguese cuspidor "spittoon," from cuspir "to spit," from Latin conspuere "spit on," from assimilated form of com-, here perhaps an intensive prefix (see com-), + spuere "to spit" (see spew (v.)).
<a href="https://www.etymonline.com/word/humidor">Etymology of humidor by etymonline</a>
Harper, D. (n.d.). Etymology of humidor. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/humidor