Meths is British informal English for methylated spirits: strong alcohol with extra chemicals mixed in so it is not meant for drinking. People use it as fuel for small camping stoves, as a cleaner, or sometimes to stop things freezing. It smells sharp, it burns easily, and it is poisonous if you drink it. In the UK, meths is the everyday short word; American English usually says denatured alcohol instead, and does not use meths for this. Though actually, some people in the past did drink meths because it was cheap, which is why older British English sometimes links the word with people living on the street. That use is dated and unkind; the ordinary meaning now is the liquid itself. This is not the drug meth (methamphetamine). They only look similar on the page.

變性酒精（英式口語；美式較常說 denatured alcohol。不是毒品 meth）