This is the 200th most frequent Dutch word.
zijn
"Zijn" means "to be."
Here, "ben" is a conjugation of the verb "zijn" in the first person singular, used as a linking verb to describe a state of being.
Ik ben gelukkig vandaag.
I am happy today.
Here, "is" is a conjugation of the verb "zijn" in the third person singular, used to indicate location or existence.
Het boek is op de tafel.
The book is on the table.
Here, "zijn" is a possessive pronoun, meaning "his," showing possession or relation.