English and Scottish of uncertain origin. The surname is believed to have originated from one of a number of habitation names based on Old Welsh "stone".

Charnock was a forename in male and female forms in England during the 17^th-19^th centuries.  We are uncertain if the male form is equivalent to Charles.  However a correspondent [GJ] has an female ancestor whose birth name was Charnock but she was known as Charlotte when she married.