EEG vs encephalogram

EEG and encephalogram both are nouns.

Word	Noun	Adjective	Verb	Adverb
EEG	Yes	No	No	No
encephalogram	Yes	No	No	No

As nouns, EEG and encephalogram are synonyms defined as:

EEG and encephalogram: a graphical record of electrical activity of the brain; produced by an electroencephalograph

Other synonyms of EEG include electroencephalogram.

EEG (noun)	encephalogram (noun)
a graphical record of electrical activity of the brain; produced by an electroencephalograph	an X ray of the brain made by replacing spinal fluid with a gas (usually oxygen) to improve contrast
	a graphical record of electrical activity of the brain; produced by an electroencephalograph