Och is a little spoken word you hear in Scotland and in parts of Ireland. People say it when they are surprised, when they want to soften a remark, or when they are about to explain themselves: Och, I didn’t mean that. Och, that’s a shame. It works a bit like oh or ah in other kinds of English, but it carries a Scottish or Irish voice with it. You will almost never need it in a school essay; it belongs to speech, stories, and dialogue on the page. Though actually, some learners only meet the tourist phrase och aye (“oh yes”), which is real enough but easy to overdo. Scottish people do not start every sentence that way, and using it as a joke accent can sound unkind.