seashore party; rocky beach festival
A casual gathering or festival held on a rocky seashore, often involving food, games, and enjoying the coastal environment. Related to 磯遊び (playing at the seashore).
See also: 磯遊び
In summer, the locals hold a seashore party and enjoy the seafood.
fishermen's celebration for a good catch; dragon god festival
A traditional celebration by fishermen to honor the dragon god after a bountiful haul. This sense is more specific and ritualistic than the general seashore party.
The fishermen held a celebration in honor of the dragon god after a good haul.
Kanji-only spelling; less common but still used.
Mixed spelling with kana for まつり; seen in informal contexts.
Compound of 磯 (いそ, 'rocky seashore') and 祭り (まつり, 'festival'). The second sense likely derives from local fishing community traditions.