What are crystalline , polycrystalline , amorphous and polymeric solids ?

The solids which have characteristic geometrical shape and sharp melting points are called crystalline solids while those which do not have any characteristic geometrical shape and don't have sharp melting point too are amorphous solids.

In some crystalline solids, the crystals are very fine and cannot be seen with naked eyes.These solids gives an impression of being amarphous.Such solids,are termed as polycrystalline solids.

 poly meaning ‘many’ and meros meaning ‘parts’. A polymeric solid is made up of small units that are joined together (like the pattern in a necklace).  These small units join together to form a single large unit called polymer or polymeric solid.