In climate and environment English, an emitter is a person, a company, or a country that produces a greenhouse gas such as carbon dioxide, or another substance that pollutes. News stories talk about “major emitters” meaning the countries that put the most of those gases into the air. The word is built simply: emit + -er, “the one that emits”. Though actually, in physics and electronics emitter means something else — a part that sends out electrons — and that is not this sense. Here we are in the green-policy sense. It can feel cold and technical; it names a source. People often use it with a frown, but the word itself only says who is sending the stuff out.