The Collaborative International Dictionary of English v.0.48:

Coeval \Co*e"val\, a. [L. coaevus; co- + aevum lifetime, age.
   See Age, n.]
   Of the same age; existing during the same period of time,
   especially time long and remote; -- usually followed by with.
   [1913 Webster]

         Silence! coeval with eternity!           --Pope.
   [1913 Webster]

         Oaks coeval spread a mournful shade.     --Cowper.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Coeval \Co*e"val\, n.
   One of the same age; a contemporary.
   [1913 Webster]

         As if it were not enough to have outdone all your
         coevals in wit.                          --Pope.
   [1913 Webster]

WordNet (r) 3.0 (2006):

coeval
    adj 1: of the same period [syn: coetaneous, coeval,
           contemporaneous]
    n 1: a person of nearly the same age as another [syn:
         contemporary, coeval]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "coeval":
   accompanying, agreeing, atavistic, bodily, born, coetaneous,
   coeternal, coexistent, coexisting, coinstantaneous, collateral,
   concomitant, concurrent, congenital, connatal, connate, connatural,
   constitutional, contemporaneous, contemporary, conterminous,
   coterminous, dead heat, draw, genetic, hereditary, in the blood,
   inborn, inbred, incarnate, indigenous, inherited, innate,
   instinctive, instinctual, isochronal, isochronous, native,
   native to, natural, natural to, organic, physical, primal,
   simultaneous, synchronal, synchronic, synchronous, temperamental,
   tie, unison, unisonous