from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A person 50 years old, or in his or her fifties.
- adj. Of or characteristic of a person in his or her fifties.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. One who is between the age of 50 and 59, inclusive.
- adj. Being between the age of 50 and 59, inclusive.
- adj. Of or relating to a quinquagenarian.
from The Century Dictionary and Cyclopedia
- Being fifty years of age.
- n. A person aged fifty or between fifty and sixty.
From Latin quīnquāgēnārius, containing fifty, from quīnquāgēnī, fifty each, from quīnquāgintā, fifty; see penkwe in Indo-European roots.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin quinquagenarius ("containing fifty"), from quinquegeni ("fifty each"), from quinquaginta ("fifty") + -an (Wiktionary)