From WordNet (r) 3.0 (2006) [wn]:
June
n 1: the month following May and preceding July
From The Collaborative International Dictionary of English v.0.48 [gcide]:
June \June\, n. [L. Junius: cf. F. Juin. So called either from
Junius, the name of a Roman gens, or from Juno, the goddess.]
The sixth month of the year, containing thirty days.
[1913 Webster]
And what is so rare as a day in June?
Then, if ever, come perfect days. --Lowell.
[1913 Webster]
June beetle, June bug (Zool.), any one of several species
of large brown beetles of the genus Lachnosterna and
related genera; -- so called because they begin to fly, in
the northern United States, about the first of June. The
larv[ae] of the June beetles live under ground, and feed
upon the roots of grasses and other plants. Called also
May bug or May beetle.
June grass (Bot.), a New England name for Kentucky blue
grass. See Blue glass, and Illustration in Appendix.
[1913 Webster]