DIFFERENT is an adjective. e.g. "Birds and reptiles are different." OR "She is different." OR "I don't want to take a different route."
DIFFERENCE is a noun. We must say "The difference" e.g. "I can't see the difference." OR "What's the difference?"
USAGE with BETWEEN:
1. THE differeNCE between A and B is (that) + SVO.(subject+verb+object)
e.g. The difference between weather and climate is that (weather describes the conditions over a short period of time) WHEREAS (climate describes the conditions over a longer period of time.)
We can also do away with THAT.
2. THE differeNCE between As (plural) and Bs(plural) is that + SVO
e.g. The difference between birds and reptiles is that MOST BIRDS FLY (this is an SVO sentence) and MOST REPTILES CREEP on their stomachs (another SVO sentence)
Here too, we can do away with THAT.
3. The difference between A and B is / is not + phrase
e.g. The difference between medicine and poison IS NOT ALWAYS CLEAR.
The difference between medicine and poison is IN THE DOSE.
The difference between weather and climate is A MEASURE OF TIME.
Hope this helps you to use the phrase in real-life situations.