sul·fate 
(sŭlfāt′)
(sŭlfāt′)n.
The divalent group SO4 or a compound containing this group.
v. sul·fat·ed, sul·fat·ing, sul·fates
v.tr.
1. To treat or react with sulfuric acid or a sulfate.
2. Electricity To cause lead sulfate to accumulate on (the plates of a lead-acid storage battery).
v.intr.
To become sulfated.
[French, from Latin sulfur, sulfur.]