Meaning

noun an electronic device that doubles the voltage or the frequency of an input signal

adjective having more than one decidedly dissimilar aspects or qualities; ; - R.W.Emerson; -Frederick Harrison

adjective consisting of or involving two parts or components usually in pairs

originEtymology tree English double 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 doubler From double (adjective) + -er.

Etymology from Wiktionary, CC BY-SA 3.0