upbeat

adj. optimistic, cheerful

n. (Music) unaccented beat that precedes an accented downbeat; upward movement of the hand made by a musical conductor to indicate an unaccented beat

Upbeat (Ger. Auftakt).1. An unaccented beat or beats that occur before the first beat of a following measure. Also called anacrusis or pickup. In other words, this is an impulse in a measured rhythm that immediately precedes, and hence anticipates, the downbeat, which is the strongest of such impulses. It can be the last beat in a bar where that bar precedes a new bar of music.
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Noun
1. a contented state of being happy and healthy and prosperous; "the town was finally on the upbeat after our recent troubles"
(synonym) wellbeing, well-being, welfare, eudaemonia, eudaimonia
(hypernym) prosperity, successfulness
(hyponym) fool's paradise
2. an unaccented beat (especially the last beat of a measure)
(hypernym) rhythm, beat, musical rhythm
Adjective
1. pleasantly (even unrealistically) optimistic
(synonym) cheerful, pollyannaish
(similar) optimistic