Answer:
A solid has definite volume and definite shape, a gas has neither definite volume nor definite shape, and as said in the question, a liquid has a definite volume but no definite shape.
What this means is that even though liquid molecules can slide past each other and move to fill up the space they are in (this means that liquids have no definite shape), they keep their volume. That is, liquids have consistent, unchanging volume.
Hopefully that's helpful! :)
