They usually share a set of features in terms of typing, extensibility, ability to be used more as glue language than real applications, interactivity
A well known paper that discusses those capabilities is the John Ousterhout's paper for the 1998 IEEE COMPUTER, "Scripting: Higher Level Programming
for the 21st Century".
The problem is that many discuss what they think a certain programming language is, without the proper bases to do so.