Singular = lens
Plural = lenses
Anyway I think it's still quite worthwhile to get a drybox (cheaper) or a dry cabinet (more ex, but better regulation of humidity). They don't cost A LOT of money.
For D60 + dual lens kit + flash + filters, a 30L dry cabinet should be sufficient.
Unless you're planning on buying more lenses in the near or medium-term future, then perhaps get a larger dry cabinet.