Leuco- \Leu"co-\ (l[=u]"k[-o]-), Leuc- \Leuc-\ (l[=u]k-). pref.
[Gr. leyko`s white.]
A combining form signifying white, colorless; specif.
(Chem.), denoting an extensive series of colorless organic
compounds, obtained by reduction from certain other colored
compounds; as, leucaniline, leucaurin, etc.
[1913 Webster]