[kal-si-tree-awl, -ol]
  1. Biochemistry. a vitamin D compound, C27H44O3, occurring in humans as a hormone derived from cholesterol, that acts in the regulation and absorption of calcium.
  2. Pharmacology. a preparation of this compound, used in the treatment of osteoporosis and bone fracture.

Origin of calcitriol

1975–80; apparently calci(um) + triol Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018