A diminutive of the female given name Catherine and of its variant forms, also used as a formal given name in the 20th century.
It was named Catherine, but he never called it the name in full, as he had never called the first Catherine short, probably because Heathcliff had a habit of doing so. The little one was always Cathy, it formed to him a distinction from the mother, and yet, a connection with her; ( - - - ) 1847 December, Ellis Bell [pseudonym; Emily Brontë], Wuthering Heights: […], volume (please specify |volume=I or II), London: Thomas Cautley Newby, […], →OCLC:
'Cathy sounds like the name of a truck-stop waitress,' she overheard her father-in-law tell Adam after they returned from their honeymoon. 'Tell her to call herself Cat and, for Christ's sake, get her to stop biting her lip all the time.' 2007, Kate Jacobs, The Friday Night Knitting Club, Hodder & Stoughton, →ISBN, page 124: