This is the 72nd most frequent German word.
ihrer
"ihrer" means "her," "their," or "of her/them" depending on context.
Used as a possessive pronoun (their/your).
Ihre Katze spielt mit dem Ball.
Your cat is playing with the ball.
Refers to the genitive case (of them).
Wir werden ihrer gedenken.
We will remember them.
Indicating possession for a plural subject in genitive case.