Question

Difference between dictionary and glossary

Answer 1

Dictionary gives meaning of all the words while glossary gives meaning of the words in a particular work. For example. the meanings of the words in a particular story will collectively be termed as glossary

Answer 2

A dictionary is a book which defines many random words, a glossary is at the end of a book/article it defines some of the words used in the previous pages. 
Hope this helps you some!