sales vs gross sales

sales and gross sales both are nouns.

Word	Noun	Adjective	Verb	Adverb
sales	Yes	No	No	No
gross sales	Yes	No	No	No

As nouns, sales and gross sales are synonyms defined as:

sales and gross sales: income (at invoice values) received for goods and services over some given period of time

Other synonyms of sales include gross revenue.

sales (noun)	gross sales (noun)
income (at invoice values) received for goods and services over some given period of time	income (at invoice values) received for goods and services over some given period of time