Words from the author: "For so many years I always thought that P.S. stands for "please see" but I was wrong :E"
This is what I found after googling
"P.S. stands for "postscript"[Press ctrl+A]. It means something added after a letter or other written communication. Like to add a detail.
For example
Dear Christmas,
Its been fun, the kids are learning, and thanks for everything. Its really pretty.
p.s. its really cold, you'll like it."
