diam vs diameter

diam and diameter both are nouns.

Word	Noun	Adjective	Verb	Adverb
diam	Yes	No	No	No
diameter	Yes	No	No	No

As nouns, diam and diameter are synonyms defined as:

diam and diameter: the length of a straight line passing through the center of a circle and connecting two points on the circumference

diam (noun)	diameter (noun)
the length of a straight line passing through the center of a circle and connecting two points on the circumference	the length of a straight line passing through the center of a circle and connecting two points on the circumference
	a straight line connecting the center of a circle with two points on its perimeter (or the center of a sphere with two points on its surface)