From an unused root meaning to be dumb (compare damah); silence; figuratively, death -- silence.
see HEBREW damah
H1745. dumah
I. דּוּמָה noun feminine silence; — ׳ד = שְׁאוֺל Psalm 94:17, ד ׳יֹרְדֵי 115:17; also Isaiah 21:11 דּוּמָה מַשָּׂא oracle of silence, i.e. of concealment, hidden meaning, according to Ew Di, but see II. ׳ד, 3