late 14c., "minute opening, small orifice, or perforation" in the earth, a tree, the body of a human, animal, or insect, a bone, etc.," from Old French pore (14c.) and directly from Latin porus "a pore," from Greek poros "a pore," literally "passage, way," from PIE *poro- "passage, journey," suffixed form of PIE root *per- (2) "to lead, pass over."
word-forming element expressing state or condition, in medical terminology denoting "a state of disease," from Latin -osis and directly from Greek -osis, formed from the aorist of verbs ending in -o. It corresponds to Latin -atio.
<a href="https://www.etymonline.com/word/osteoporosis">Etymology of osteoporosis by etymonline</a>
Harper, D. (n.d.). Etymology of osteoporosis. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/osteoporosis