Morrow vs. Tomorrow [closed]

What's the difference between morrow and tomorrow? Why are there two similar words for the same meaning?

I noticed it in the title of a song of Michael Nyman, "Second Morrow", on Gattaca OST.

There is no sign that it was an ancient word.


Morrow is "the day after"; All Souls' Day is the morrow of All Saints' Day. Tomorrow is simply 'today's morrow', as today was yesterday's morrow.

But, as others have said, morrow is currently little used compared with tomorrow.