The story
From (py)ri(dinyl) + -se- (of unknown origin) + -dronic (“calcium metabolism regulator”) acid.
Etymology from Wiktionary, CC BY-SA 4.0.
risedronic acid
Today it means: A bisphosphonate C₇H₁₁NO₇P₂ taken orally to inhibit bone resorption especially in the prevention or treatment of osteoporosis in postmenopausal women. Full definition →