Methyl \Meth"yl\, n. [See Methylene.]

(Chem.) A hydrocarbon radical, CH3, not existing alone but regarded as an essential residue of methane, and appearing as a component part of many derivatives; as, methyl alcohol, methyl ether, methyl amine, etc. [Formerly written also methule, methyle, etc.]

Methyl alcohol (Chem.), a light, volatile, inflammable liquid, CH3.OH, obtained by the distillation of wood, and hence called wood spirit

Source: Webster's Revised Unabridged Dictionary (1913)
 

Formyl \For"myl\, n. [Formic + -yl.]

(Chem.)
   (a) A univalent radical, H.C:O, regarded as the essential residue of formic acid and aldehyde.
   (b) Formerly, the radical methyl, CH3.

Source: Webster's Revised Unabridged Dictionary (1913)