As nouns the difference between tan and tans

is that tan is a yellowish-brown colour while tans is plural of lang=en.

As verbs the difference between tan and tans

is that tan is to change to a tan colour due to exposure to the sun while tans is third-person singular of tan.

As an adjective tan

is of a yellowish-brown.

As a numeral tan

is the second cardinal number two, formerly used in Celtic areas, especially Cumbria and parts of Yorkshire, for counting sheep, and stitches in knitting.See Wikipedia article on Yan Tan Tethera

As a proper noun Tan

is an English surname derived from the transliteration of various Asian surnames, particularly originating from China and Vietnam.

As an initialism TAN

is Total Acid Number, the measure of a lubricant's or crude oil's acidity.