The British royal family is known for following specific rules and protocols. What the public may not know is that there are also some words they probably shouldn’t say to the reigning monarch.

Last October, US Weekly reported that Queen Elizabeth II isn’t fond of one word in particular: pregnant. “Her Majesty finds the term ‘vulgar’,” the outlet reported at the time. According to a palace source, the Queen prefers to use the term “in the family way” when discussing someone who is expecting a child.

The outlet Family Education explained the Queen’s aversion to the word, writing earlier this year, “Many may think this is prudish, but the Queen must always speak with propriety, and let’s remember she’s from a different era when the word ‘pregnant’ would never have been considered suitable to be uttered in public... Also keep in mind that the Queen is [93-years-old] and words we use without a thought today, were once considered inappropriate; ‘pregnant’ being one of them. She’s also a royal and their language usage isn’t your typical everyday banter around the water cooler.”

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Backing up this claim, Express reports that when Queen Elizabeth learned she was expecting her first child with husband Prince Philip in 1948, the topic of pregnancy was “almost taboo.” Unlike current royal pregnancy announcements that are published on social media, the Queen’s announcement was cryptic, reading, “Her Royal Highness the Princess Elizabeth will undertake no public engagements after the end of June.” What followed was Elizabeth withdrawing from the public for several months before welcoming son Prince Charles later that same year.

Pregnant is not the only word that is reportedly frowned upon using around the royal family. Reader’s Digest reported that the word toilet is also “banned in royal circles” as are the words posh, refreshments, mum, and dad.

Queen Elizabeth II
Queen Elizabeth II smiles as she arrives before the Opening of the Flanders' Fields Memorial Garden at Wellington Barracks on Nov. 6, 2014, in London, England. Getty Images/Stefan Wermuth-WPA Pool