The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.

colcothar


SYLLABICATION:
col·co·thar
PRONUNCIATION:
klk-thr, -thär
NOUN:
A brownish-red ferric oxide obtained as a residue after heating ferrous sulfate,
used in glass polishing and as a pigment.
ETYMOLOGY:
Medieval Latin, from Spanish colcótar, from Arabic qulqur, possibly from
Greek khalkanthos, copper sulfate : khalkos, copper + anthos, flower.