There are number of definitions of glass which have different approaches.
There is no universally accepted or universal
definition of glass.
It is a fusion product of materials which have been cooled to a rigid condition with out crystallization(It need not be inorganic).
Examples of familiar glasses made from cane sugar are lollipops and cotton candy. The former are in shape of rigid block and latter are flexible fibers.
Other definitions:
1) An Amorphous solid or glass is one in which long range order is absent and the array of equilibrium atomic positions is strongly disordered.
2) Glass is an uncrystallized solid material.
3) Glass is an inorganic product of fusion which has been cooled to a rigid condition with out crystallizing.
4) A general definition including all the aspects of glass is not possible; glass is to be conceived on one hand as a physical chemical condition and on other hand as a technical material.
