 Later it came to be used as a first name.It is also possible that the name Garth comes from the Welsh name 'Gareth', Gareth [ˈɡarɛθ] is a Welsh masculine given name of uncertain meaning.It first appeared in this form in Thomas Malory's Le Morte d'Arthur, in which it belonged to Sir Gareth, a brother of Gawain and one of the Knights of the Round Table.