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Wiktionary
methyl methacrylate

n. (context organic compound English) The methyl ester of methacrylic acid, CH2:C(CH3)COOCH3, used as a monomer in the manufacture of polymethyl methacrylate plastics.

Wikipedia
Methyl methacrylate

Methyl methacrylate (MMA) is an organic compound with the formula CH=C(CH)COOCH. This colourless liquid, the methyl ester of methacrylic acid (MAA) is a monomer produced on a large scale for the production of poly(methyl methacrylate) (PMMA).

Methyl methacrylate (data page)

This page provides supplementary chemical data on Methyl methacrylate.