delta wave vs delta rhythm

delta wave and delta rhythm both are nouns.

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

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

delta wave and delta rhythm: 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 wave (noun)	delta rhythm (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)