Merriam-Webster Collegiate Dictionary - levigate

 transitive verb  (-gated; -gating)  Etymology: Latin levigatus, past participle of levigare to make smooth, from levis smooth (akin to Greek leios smooth and perhaps to Latin linere to smear) + -igare (akin to agere to drive) — more at lime, agent  Date: 1612  1. polish, smooth  2.  a. to grind to a fine smooth powder while in moist condition  b. to separate (fine powder) from coarser material by suspending in a liquid  • levigation noun