Meaning

noun a substance capable of bringing about the reduction of another substance as it itself is oxidized; used in photography to lessen the density of a negative or print by oxidizing some of the loose silve

noun pipefitting that joins two pipes of different diameter

originEtymology tree English reduce Proto-Indo-European *-yósder. Proto-Italic *-āzijos Latin -āriusnom. Latin -āriusbor. Proto-Germanic *-ārijaz Proto-West Germanic *-ārī Old English -ere Middle English -ere English -er English reducer From reduce + -er.

Etymology from Wiktionary, CC BY-SA 3.0