The Collaborative International Dictionary
Metol
Metol \Me"tol\, n. [G.; trade name, fr. meta- + kresol cresol.] A whitish soluble powder used as a developer in photography. Chemically, it is the sulphate of methyl-p-amino-m-cresol.
Wiktionary
metol
n. (context chemistry photography English) The sulphate of 4-methylaminophenol, used as a photographic developer
Wikipedia
Metol
Metol is the organic compound with the formula [HOCHNH(CH)]HSO. It is the hydrogen sulfate (HSO) salt of the protonated derivative of N-methylaminophenol. This colourless salt is a popular photographic developer used in black & white photography.