I used to have a cat called Bertha. She was great and I still miss her. It turns out that ‘bertha’ is also a word.
a collar or trimming, as of lace, worn about the shoulders by women, as over a low-necked waist or dress.
1835–45; named after Bertha (died a.d. 783), wife of Frankish king Pepin the Short; she was famed for her modesty
a female given name: from a Germanic word meaning “bright.”
It was one of Kitty’s happy days. Her gown did not feel tight anywhere, her lace bertha did not slip down, her rosettes were neither crumpled nor hanging off, her pink shoes with their high curved heels did not pinch but delighted her little feet.
Source: Anna Karenina by Leo Tolstoy.