A kind of electronic dance music: fast, with a strong steady beat, made with machines rather than guitars and drums, and often with few or no words. It grew up in Detroit in the mid-1980s and became club music across Europe, especially in Berlin. "They played techno all night." It is an uncountable noun, so no "a" and no plural — you listen to techno, not to a techno.

People who are into dance music use "techno" narrowly, for that specific sound, and will gently correct you if you call house or trance techno — those are neighbours, not the same thing. Outside those circles, plenty of people use "techno" loosely for any thumping electronic music, and that use is very common in ordinary conversation.

It also works before a noun: "a techno club", "a techno track", "techno music" (that last one is a bit redundant, but everyone says it).

Separately, techno- turns up as a word-beginning meaning "technology": techno-fear, techno-babble, technophobe. That is a different job for the same piece, and you can usually tell them apart instantly — one is music, the other is glued to another word.