Origin of litmusOld Norse litmose, lichen used in dyeing from litr, color (akin to Gothic wlits, face from Indo-European an unverified form w?tu-, appearance from base an unverified form wel-, to see from source Classical Latin voltus, expression, Welsh gweled, to see) + mosi, moss
Origin of litmusMiddle English litemose ( of Scandinavian origin ) (Old Norse litmosi dyer's herbs ) ( litr color, dye ) ( mosi bog, moss )Middle English lykemose ( from Middle Dutch lijkmoes ) ( variant of lēcmoes ) ( lēken to drip ) ( moes moss )
(countable and uncountable, plural litmuses)
1495, earlier lytmos, from Old Norse litmosi (“moss used for dyeing"), from lita (“to dye, stain"), from litr (“colour, dye, blee"), from Proto-Germanic *wlitiz, *wlituz (“appearance, blee"), from Proto-Indo-European *wel- (“to see") + mosi (“moss"). Cognate with Old English wlite (“appearance, form, brightness, countenance"). More at moss.