Pendragon

Pendragon or Pen Draig (Middle Welsh pen[n] dragon, pen[n] dreic; composed of Welsh pen, "head, chief, top" and draig/dragon, "dragon; warrior"; borrowed from the Latin word dracō, plural dracōnēs, "dragon[s]") literally means "Chief-Dragon" or "Head-Dragon", but in a figurative sense, "chief leader", "chief of warriors", "commander-in-chief", "generalissimo", or "chief governor".  is the epithet of Uther, father of King Arthur in medieval and modern Arthurian literature and occasionally applied to historical Welsh heroes in medieval Welsh poetry, such as Rhodri ab Owain Gwynedd.

In the Historia Regum Britanniae, one of the earliest texts of the Arthurian legend, only Uther is given the surname "Pendragon", which is explained by the author Geoffrey of Monmouth as literally meaning "dragon's head".

In the prose version of Robert de Boron's Merlin, the name of Uther's elder brother Ambrosius is given as "Pendragon", while Uter (Uther) changes his name after his brother's death to "Uterpendragon".

The use of "Pendragon" to refer to Arthur, rather than to Uther or his brother, is of much more recent vintage. In literature, one of its earliest uses to refer to Arthur is in Alfred Tennyson's poem Lancelot and Elaine, where, however, it appears as Arthur's title rather than his surname, following contemporary speculation that "pendragon" had been a term for an ancient Welsh war-chief.

Mark Twain in A Connecticut Yankee in King Arthur's Court makes various satirical and scathing remarks about "The Pendragon Dynasty" which are in fact aimed at ridiculing much later British dynasties.

...
Wikipedia