interstellar

As a letter s

is the letter s with a.

As an adjective interstellar is

between the stars.

As a noun mythos

is myth, mythos (a story relevant to a particular culture or some other group).

As an adjective interstellar is

between the stars.

As adjectives the difference between milky and interstellar

is that milky is resembling milk in color or consistency while interstellar is between the stars.

As adjectives the difference between interstellar and interdimensional

is that interstellar is between the stars while interdimensional is between dimensions.

As adjectives the difference between interstellar and galactic

is that interstellar is between the stars while galactic is pertaining to the milky way galaxy.

As adjectives the difference between extraterrestrial and interstellar

is that extraterrestrial is originating from outside of the earth's atmosphere, from space, or from another planet; alien to earth or its environment while interstellar is between the stars.

As a noun extraterrestrial

is a being originating from outside of the earth's atmosphere, from space, or from another planet; an alien.

As adjectives the difference between extraplanetary and interstellar

is that extraplanetary is originating, or located outside of a planet while interstellar is between the stars.

As adjectives the difference between interstellar and galaxywide

is that interstellar is between the stars while galaxywide is throughout a galaxy.

As a noun galaxy

is the Milky Way; the apparent band of concentrated stars which appears in the night sky over earth.

As a proper noun Galaxy

is the Milky Way Galaxy, from when it was thought the Universe (our universe) had only one galaxy.

As an adjective interstellar is

between the stars.