noun
small fish pickled in vinegar, sake, and salt
Traditional preparation where small fish are sliced open and pickled in a mixture of vinegar, sake, and salt. Often made with fish like 小鯛 (kodai) or あじ (aji).
この沖漬けは、酢と酒と塩だけで漬けてあります。
This okizuke is pickled only with vinegar, sake, and salt.
noun
seafood pickled in soy sauce (esp. squid)
More common modern usage: seafood, especially squid, pickled in a soy-sauce-based marinade. Often served as a side dish or with alcohol.
イカの沖漬けはご飯にも酒にも合う。
Squid okizuke goes well with both rice and alcohol.
漬物 is a general term for pickled vegetables, while 沖漬け specifically refers to pickled seafood.
粕漬け is pickled in sake lees, whereas 沖漬け uses vinegar/sake/salt or soy sauce.
From 沖 (oki, 'offshore') + 漬け (zuke, 'pickling'), referring to seafood pickled soon after being caught at sea.