Rhema (ῥῆμα in Greek) literally means an "utterance" or "thing said" in Greek. It is a word that signifies the action of utterance.
In philosophy, it was used by both Plato and Aristotle to refer to propositions or sentences.
In Christianity, it is used in reference to the concept of Rhematos Christou; Jesus Christ's sayings.
Read more about Rhema: Etymology, Greek Philosophers, Rhema and Logos in Christianity