As nouns the difference between tas and fas

is that tas is an alternative spelling of lang=en while fas is plural of lang=enCategory:English plurals.

As an acronym TAS

is tool-assisted speedrun.

As an abbreviation TAS

is abbreviation of lang=en|Tasmania.

As an adjective TAS

is used to describe any tool-assisted project.

As a verb TAS

is to make, create, or contribute to a tool-assisted speedrun.

As an initialism FAS is

fetal alcohol syndrome.