Often written 哎哟 — same word, alternate spelling. Use it for sudden pain ('ouch'), pleasant surprise, or mild dismay. Tone is casual and very common in spoken Mandarin.
memory
Made famous internationally by the 2014 Chinese hit song 哎呦不错哦 (Āiyōu, búcuò ó — 'Wow, not bad!'), later sampled into countless memes.
