Wiktionary
osteopenia
n. The medical condition of having low bone density, but not low enough to be considered osteoporosis.
Wikipedia
Osteopenia
Osteopenia is a condition in which bone mineral density is lower than normal. It is considered by many doctors to be a precursor to osteoporosis. However, not every person diagnosed with osteopenia will develop osteoporosis. More specifically, osteopenia is defined as a bone mineral density T-score between -1.0 and -2.5.