A hopefully short and concise explanation as to how Clojure deals with Objects. If you already write Clojure, this isn't for you.
You know what an Interface is if you write/read Java or PHP 5+. In Clojure it might be called defprotocol.
user> (defprotocol IABC
(also-oo [this])
(another-fn [this x]))
IABC