Source : Webster's Revised Unabridged Dictionary (1913)

Summer \Sum"mer\, v. i. [imp. & p. p. {Summered}; p. pr. & vb.
   n. {Summering}.]
   To pass the summer; to spend the warm season; as, to summer
   in Switzerland.

         The fowls shall summer upon them.        --Isa. xviii.
                                                  6.