What is polymer?

POLYMERS - POLY means MANY and MERS means UNITS or PARTS.
These are giant molecules of high molecular masses built-up by the linking together of large number of molecules.

For examples-polythene
It is polymer formed by linking together of a large number of ethene molecules.

MONOMERS- small molecules which combine with each other to form polymers are known as monomers.
And the repeat unit in polymer is known as mer.