enamel: [14] The underlying meaning element in enamel is ‘melting’. It comes ultimately from a prehistoric Germanic base *smalt- (source of English schmaltz ‘sentimentality’ [20], borrowed via Yiddish from German schmalz ‘fat, dripping’), and related Germanic forms produced English smelt, melt, and malt. Old French acquired the Germanic word and turned it into esmauz; this in turn was re-formed to esmail, and Anglo-Norman adopted it as amail.
This formed the basis, with the prefix en- ‘in’, of a verb enamailler ‘decorate with enamel’. English borrowed it, and by the mid-15th century it was being used as a noun for the substance itself (the noun amel, a direct borrowing from Anglo-Norman, had in fact been used in this sense since the 14th century, and it did not finally die out until the 18th century).
Its application to the substance covering teeth dates from the early 18th century. => malt, melt, schmaltz, smelt
enamel (v.)
early 14c., from Anglo-French enamailler (early 14c.), from en- "in" (see en- (1)) + amailler "to enamel," variant of Old French esmailler, from esmal "enamel," from Frankish *smalt, from Proto-Germanic *smaltjan "to smelt" (see smelt (v.)). Related: Enameled; enameler; enameling.
enamel (n.)
early 15c., in ceramics, from enamel (v.). As "hardest part of a tooth," 1718, from a use in French émail.