1.
excitement, enthusiasm, liveliness
A state of heightened energy, excitement, or enthusiasm in a group or at an event. Describes the atmosphere when people are energized and engaged.
Usage
The nominal form of the verb 盛り上がる (to get excited, to swell). Sense 1 (excitement/enthusiasm) is by far the more common usage. Often describes the atmosphere at events, parties, concerts, and sporting matches. The phrase 盛り上がりに欠ける (to lack excitement) is used for disappointingly flat events.