The act or result of washing something; the noun form of 'to wash'.
洗いが終わったら、タオルで水気を拭いてください。
After washing, please wipe off the moisture with a towel.
下洗いをしてから本洗いに入る。
Do a preliminary wash before the main washing.
この服は洗いが甘いと汚れが残りやすい。
If the washing is insufficient, stains tend to remain on these clothes.
In culinary contexts, sashimi chilled in iced water (a preparation method and the dish resulting from it).
鯛の洗いには酢味噌をつけて食べるのが定番だ。
It's customary to eat sea bream 'arai' with vinegared miso.
関西では『洗い』という料理名で出されることが多い。
In Kansai it is often served under the name 'arai'.