The Collaborative International Dictionary of English v.0.48:

Contemporaneous \Con*tem`po*ra"ne*ous\, a. [L. contemporaneus;
   con- + tempus time. See Temporal, and cf.
   Contemporaneous.]
   Living, existing, or occurring at the same time;
   contemporary.
   [1913 Webster]

         The great age of Jewish philosophy, that of Aben Esra,
         Maimonides, and Kimchi, had been contemporaneous with
         the later Spanish school of Arabic philosophy. --Milman
   -- Con*tem`po*ra"ne*ous*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

contemporaneous
    adj 1: occurring in the same period of time; "a rise in interest
           rates is often contemporaneous with an increase in
           inflation"; "the composer Salieri was contemporary with
           Mozart" [syn: contemporaneous, contemporary]
    2: of the same period [syn: coetaneous, coeval,
       contemporaneous]

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "contemporaneous":
   accompanying, actual, agreeing, as is, being, coetaneous,
   coeternal, coeval, coexistent, coexisting, coinstantaneous,
   collateral, concomitant, concurrent, contemporary, conterminous,
   coterminous, current, existent, existing, extant, fresh, immanent,
   immediate, instant, isochronal, isochronous, latest, modern, new,
   present, present-age, present-day, present-time, running,
   simultaneous, synchronal, synchronic, synchronous, that be,
   that is, topical, unison, unisonous, up-to-date,
   up-to-the-minute