means A sequence is a set of things arranged one after another in a particular order, each item following from the last.

from From Latin 'sequi,' to follow — the same root that trails through 'consequence,' 'sequel,' and 'pursue.' Medieval Latin made 'sequentia' (a following), and English took it on. So at heart a sequence is simply a thing that follows: footstep after footstep, each item shadowing the one before.