What is Mz. the abbreviation of in German?

I've done a google search, looked through lists of abbreviations and checked here and and I can't find the answer.

This keeps appearing in Coop/Migros crosswords, e.g. "weibl. Verwandte Mz.".

Any ideas? Thanks!

Mehrzahl - Plural?

Correct.

Thanks both!

I'd like to say that makes the whole crossword make more sense, but not quite

Tanten ?

Yup, crosswords and Tanten. Reminds me of this old joke (I feel entitled to go off-topic since the OP's problem has been solved):

One day, a shy gentleman was preparing to board a plane when he heard that the Pope was on the same flight.

"This is exciting," thought the gentleman. "I've always been a big fan of the Pope. Perhaps I'll be able to see him in person."

Suddenly, the man realized his seat was right next to the Pope himself.

Still, the gentleman was too shy to speak to the Pope.

Shortly after take-off, the Pope took a crossword puzzle out off his bag and began working on it.

This is fantastic, thought the gentleman. I'm really good at crosswords. Perhaps if the Pope gets stuck, he'll ask me for assistance.

After a while, the Pope turned to the man and said, "Excuse me, but do you know a four letter word referring to a woman that ends in 'unt'?

The man was in shock. He could only think of one word that fit the description and he was not about to say it to the Pope. The gentleman thought for a while longer, then it hit him.

Turning to the pope, the gentleman said, "I think you're looking for the word 'aunt'."

"Of course," said the Pope. "Do you have an eraser?"