bimillennium

[ bahy-mi-len-ee-uh m ]
/ ˌbaɪ mɪˈlɛn i əm /

noun, plural bi·mil·len·ni·ums, bi·mil·len·ni·a [bahy-mi-len-ee-uh] /ˌbaɪ mɪˈlɛn i ə/.

a period of two thousand years.
a two thousandth anniversary.
Also bimillenary, bimillennial.

Origin of bimillennium