Dear Student
Anything that has mass and occupies space is called matter.
The three states of matter are:
Solid: Here atoms or molecules are arranged strongly bound to one another forming rigid nature. Attractive forces are very strong. They have definite shape and sizes. E.g. ice, diamond, table, book etc.
Liquid: Here atoms or molecules are not strongly bounded as in solids and will have free movement of atoms. They do have attractive forces but not as strong as in solids. They have definite volume but do not have definite shape. They take the shape of the container in which they are kept. E.g. water, alcohol etc.
Gases: Here atoms or molecules are far apart as they are not bounded at all. They do not have attractive forces but only repulsive forces. They do not have definite shape or volume but takes the shape and volume of the container in which they are placed. E.g. oxygen, helium etc.
The other two states of matter exist at extreme temperatures. These are:-
Plasma and
Bose - Einstien Condensate.
Regards