delta rhythm vs delta wave

delta rhythm and delta wave both are nouns.

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

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

delta rhythm and delta wave: the normal brainwave in the encephalogram of a person in deep dreamless sleep; occurs with high voltage and low frequency (1 to 4 hertz)

delta rhythm (noun)	delta wave (noun)
the normal brainwave in the encephalogram of a person in deep dreamless sleep; occurs with high voltage and low frequency (1 to 4 hertz)	the normal brainwave in the encephalogram of a person in deep dreamless sleep; occurs with high voltage and low frequency (1 to 4 hertz)