Definition of "meth"

meth¹

/mɛθ/

noun
countable and uncountable, plural meths
1. (informal) Methamphetamine, especially in the form of the crystalline hydrochloride.

meth²

/mɛθ/

noun
countable and uncountable, plural meths
1. (informal) Methadone.
  Quotations
  Dunno why you want to try and make last any longer than it already does. Meth has to be the single most wicked shit I ever involved myself with. But as far as what it actually does, your best bet would be to trot down to the local library and look it up.
  1998 November 14, Markus, “Re: METH”, in alt.recovery‎ (Usenet)

meth³

/mɛθ/

noun
plural meths
1. (derogatory, Liverpool, Manchester) A tramp.

meth⁴

/mɛθ/

noun
countable and uncountable, plural meths
1. A spiced mead, originally from Wales.
  Quotations
  The Russians, Swedes, Danes, and those of Northern Inhabitants, exceed all the rest, having made the drinking of Brandy, Aqua Vitae, Hydromel, Beer, Mum, Meth, and other Liquors in great quantitites, so familiar to them, that they usually drink our countrymen to death.
  1678, John Worlidge, Vinetum Britannicum, or a Treatise of Cider, 3rd edit.

meth⁵

/mɛθ/

noun
countable and uncountable, plural meths
1. (slang) Marijuana.