noun
fireworks display; fireworks festival
Refers to a large-scale public event where many fireworks are launched, typically in summer. Often implies a festive atmosphere with food stalls and crowds.
夏になると、各地で花火大会が開かれる。
In summer, fireworks displays are held in various places.
浴衣を着て花火大会に行くのが楽しみだ。
I'm looking forward to going to the fireworks festival wearing a yukata.
花火 means 'fireworks' in general (the objects themselves), while 花火大会 specifically refers to a large organized event or festival featuring fireworks.
Compound of 花火 (fireworks) and 大会 (large gathering, convention). The word straightforwardly means 'fireworks event'.