Vermione and Larry were in a class.
Teacher said: Absorption is a bulk phenomenon where molecules are distributed in the bulk of a substance.
Larry: If I fill my bottle with water, it must be absorbing the water because it's in the bulk of the bottle.
Vermione slapped Larry.
Why did Vermione slap Larry?
We can't really say that the water poured into a bottle has been absorbed by it and stored in the bulk. The bottle is just holding the water because of its plastic walls which prevent the water from flowing out.
But if you compare it with a sponge for example, the phenomenon is completely different. The pores in the structure of the sponge allow the water molecules to flow through the network and are retained in the bulk of the sponge. This is termed absorption.