1 dimma
1. d, (but dinimaðisk, Fb. i. 91; dimmat, part., Mar.):—to become dim; neut. or impers., um kveldit er d. tók, when it began to grow dark, Fms. viii. 305; dimmir af nótt, the night darkens, iii. 135: also of clouds, to grow dark (of a gale, storm); þá hvesti ok dimdi í fjörðinn, Espol. Árb. 1768.
                        2 dimma
2. u, f. dimness, darkness, esp. of clouds, nightfall; seglið bar í fjarðar-dimmuna, Espol. Árb. l. c.: metaph. gloom, Pass. 4. ii; the phrase, dimmu dregr á e-t, it becomes clouded, looks threatening, Band. 10.