Definitions for "Upbeat"
a weak beat preceding the downbeat
an unaccented beat (especially the last beat of a measure)
The beat which immediately precedes the "downbeat" or first beat of each measure. Derivatively "up-beat" comes from the motion of the conductor's hand/baton before s/he comes to the first beat of the measure or the "down-beat."
Keywords:  vortakt, auftakt, ger
Upbeat (Ger. Auftakt, Vortakt).
pleasantly (even unrealistically) optimistic
Keywords:  vivace, vivo, incomplete, note, lively
The note(s) of an incomplete opening measure. vivace :: Quickly, very lively. vivo :: With life; lively.
a contented state of being happy and healthy and prosperous; "the town was finally on the upbeat after our recent troubles"
Keywords:  month, day, good, point, one
a good day, at one point I was up for the month