Not small town nor big city

I have never lived in a big city nor a small town. I was born in Chicago, Illinois and lived there until I was 13. We had a Chicago zip code but we were not in the downtown area. When we moved, we lived in Bethesda, MD, which is a suburb of Washington DC.  Then after I married I moved to a different county in MD, then divorced and moved to a smaller county in MD. but none of these locations were big cities.and I never considered them small towns. Where I now live in WV is one of the larger counties in the state I think and definite not a small town. 
What is the definition of “small town”?
To me it seems like a place where it you knew almost everyone in town but does that exist anywhere these days? Now it seems rare if you know all the neighbors on your block.