quinquagenarian

[ kwing-kwuh-juh-nair-ee-uh n, kwin- ]
/ ˌkwɪŋ kwə dʒəˈnɛər i ən, ˌkwɪn- /

adjective

50 years of age.
between the ages of 50 and 60.

noun

a person who is 50 years old or whose age is between 50 and 60.

Origin of quinquagenarian

1560–70; < Latin quīnquāgēnāri(us) (see quinquagenary) + -an
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for quinquagenarian

quinquagenarian

/ (ˌkwɪŋkwədʒɪˈnɛərɪən) /

noun

a person between 50 and 59 years old

adjective

being between 50 and 59 years old
of or relating to a quinquagenarian

Word Origin for quinquagenarian

C16: from Latin quinquāgēnārius containing fifty, from quinquāgēnī fifty each
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012