This is the 20th most frequent Hungarian word.
aki
"Who" or "the one who."
'Aki' is used as a relative pronoun referring to 'He', serving as the subject of the relative clause.
Ő az, aki elhozza majd a könyvet.
He is the one who will bring the book.
'Aki' introduces a defining relative clause, describing and specifying which teacher is being referred to.
Az a tanár, aki tegnap új diákokat fogadott, nagyon kedves.
The teacher who welcomed new students yesterday is very kind.
'Aki' functions as a relative pronoun that introduces a relative clause, providing more information about 'someone'.