first moment vs expected value

first moment and expected value both are nouns.

Word	Noun	Adjective	Verb	Adverb
first moment	Yes	No	No	No
expected value	Yes	No	No	No

As nouns, first moment and expected value are synonyms defined as:

first moment and expected value: the sum of the values of a random variable divided by the number of values

Other synonyms of first moment include arithmetic mean, expectation.

first moment (noun)	expected value (noun)
the sum of the values of a random variable divided by the number of values	the sum of the values of a random variable divided by the number of values