The Collaborative International Dictionary
dandriff
Dandruff \Dandruff\ (d[a^]n"dr[u^]f), n. [Prob. from W. toncrust, peel, skin + AS. dr[=o]f dirty, draffy, or W. drwg bad: cf. AS. tan a letter, an eruption. [root]240.] A scurf which forms on the head, and comes off in small scales or particles. [Written also dandriff.]
Wiktionary
dandriff
n. (archaic spelling of dandruff English)