Source : Webster's Revised Unabridged Dictionary (1913)

Meantime \Mean"time`\, Meanwhile \Mean"while`\, n.
   The intervening time; as, in the meantime (or mean time).

Meantime \Mean"time`\, Meanwhile \Mean"while`\, adv.
   In the intervening time; during the interval.

Source : WordNet®

meantime
     adv : during the intervening time; "meanwhile I will not think
           about the problem"; "meantime he was attentive to his
           other interests"; "in the meantime the police were
           notified" [syn: {meanwhile}, {in the meantime}]