(defun describe-paths (location edges)
(apply #'append (mapcar #'describe-path (cdr (assoc location edges)))))
What are the similarities? Or, is there another question lurking here?
(Links from elisp, because that is what I know. The quotes are just excerpts and the links contain examples which may or may not be relevant in a particular "Lisp".)
mapcar is a function that calls its first argument with each element of its second argument, in turn. The second argument must be a sequence.
apply calls function with arguments, just like funcall but with one difference: the last of arguments is a list of objects, which are passed to function as separate arguments, rather than a single list. We say that apply spreads this list so that each individual element becomes an argument.
Happy coding.