From dragon + back, after horseback.
dragonback (uncountable)
- The back of a dragon (for riding).
2022 August 19, Jenna Scherer, “Who’s who in House Of The Dragon?”, in AV Club[1]:Princess Rhaenys Targaryen became a Velaryon when she married Lord Corlys at age 16, arriving to the wedding on dragonback—a very boss move, in our opinion.