theta wave vs theta rhythm

theta wave and theta rhythm both are nouns.

Word	Noun	Adjective	Verb	Adverb
theta wave	Yes	No	No	No
theta rhythm	Yes	No	No	No

As nouns, theta wave and theta rhythm are synonyms defined as:

theta wave and theta rhythm: the normal brainwave in the encephalogram of a person who is awake but relaxed and drowsy; occurs with low frequency and low amplitude

theta wave (noun)	theta rhythm (noun)
the normal brainwave in the encephalogram of a person who is awake but relaxed and drowsy; occurs with low frequency and low amplitude	the normal brainwave in the encephalogram of a person who is awake but relaxed and drowsy; occurs with low frequency and low amplitude