acid

An acid is a liquid with a high number of hydrogen ions in it that can burn things.

Example: Fruit often has a little acid in it.

If something is acid, it is like an acid, from an acid, or acidic.

Example: The factories nearby have made the lake more acid.

If something has an acid taste, it is sour.

If something said or done to you was acid, it was hurtful.

Example: Their acid comments are painful.