What means pas in English?

The Word pas means step when used by itself

In the negation form ne...pas, it has a no more this meaning, it's just the way of expressing a negation in french.

At some point in french language history the second Word in a sentence expressing negation was to express the smallest thing considered:

Je ne marche pas meant I don't walk, even a step

Je ne vois goutte meant I don't see, even a drop

Je ne mange mie meant I don't eat, even crumb and so on...

The french language evolving just the first form remained, now this 3 sentences are:

je ne marche pas, je ne vois pas, je ne mange pas