osteoporosis, n. [NL.; osteo- + Gr. po`ros pore.].
An absorption of bone so that the bone tissue becomes unusually porous. It occurs especially in elderly men and postmenopausal women, and predisposes the elderly to fractures of the bones. [Webster 1913 Suppl.]
osteoporosis, n. a condition of brittle and fragile bones caused by loss of bony tissue, esp. as a result of hormonal changes, or deficiency of calcium or vitamin D.