Noun: a spade, a shovel.
Let’s use lapio in a sentence: Lapioin hiekkaa lapiolla means ”I shovel sand with a shovel.”
Hiekkaa means ”sand” and appears in the partitive case.
Lapiolla is the adessive singular of lapio and means ”with a shovel.” This use of adessive is the ”instrumentive use,” i.e. it means ”with” or ”by using.”