This is the 8th most frequent Russian word.
от
"От" means "from," "of," or "by" depending on context.
"От" here expresses the origin or giver of the gift.
Это подарок от моего учителя.
This is a gift from my teacher.
"От" indicates the starting point or vantage point in this case.
Мы смотрим на город от холма.
We are looking at the city from the hill.
"От" is used here to indicate the source of the letter—who it came from.