"marks out" is a correct and usable phrase in written English.
You can use it to mean to identify or distinguish something. For example: "The bright red crayon marks out the border of the drawing."
The TTC assay essentially marks out the migration of the bacterium from the zone of inoculation by the needle.
Then he marks out a road-racing course that runs around the terrain.
So this type of integrative thinking is what marks out the most sophisticated civilizations.
She shares the balls-out "never complain, never explain" attitude that marks out a true broad.
What marks out the pop stars who die prematurely from the ones who do not?
The extraordinary rise in rents is what marks out today's student costs compared with my own.
Moving and relatively straightforward to the ear, they nevertheless have the integrity that marks out so much of his work.
What marks out Gareth Bryn as a great director?
For many, it's attitude and not dress code that marks out the modern dandy.
It was the fifth fastest swim in the world this year and marks out Jervis as a potential star.
It "marks out and defends the limits of acceptable political conduct".
