| adj. 1.  Relating to or proceeding by sixties. 2.  Sexagenarian. n. pl.   sex·ag·e·nar·ies   A sexagenarian. [Latin sexāgēnārius, from sexāgēnī, sixty each, from sexāgintā, sixty : sex, six; see  SEX- + -gintā, ten times; see  dek in the Appendix of Indo-European roots.] | 
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