add vs tot

add is not a noun while tot is a noun.

Word	Noun	Adjective	Verb	Adverb
add	No	No	Yes	No
tot	Yes	No	Yes	No

As verbs, add and tot are synonyms defined as:

Other synonyms of add include add together, add up, sum, sum up, summate, tally, tot up, total, tote up.

add (noun)	tot (noun)
	a young child who is just beginning to walk
	a small amount (especially of a drink)

add (verb)	tot (verb)
make an addition (to); join or combine or unite with others; increase the quality, quantity, size or scope of	determine the sum of
make an addition by combining numbers
determine the sum of
state or say further
bestow a quality on
constitute an addition