noun
giant snake; monster serpent
Poetic or mythological term for a huge, monstrous snake, often associated with Japanese legends like Yamata no Orochi.
ヤマタノオロチは八つの頭を持つ巨大な蛇だ。
Yamata no Orochi is a giant serpent with eight heads.
その昔話には、村を襲うオロチが登場する。
In that old tale, an orochi appears that attacks the village.
大蛇 (だいじゃ) is the standard word for a large snake, while オロチ (おろち) is a poetic or mythological term for a monstrous serpent.
The origin is uncertain; it is an ancient Japanese word for a giant serpent, famously appearing in the myth of Yamata no Orochi.