'Summersault' definitions:

Definition of 'summersault'

noun

An acrobatic feat in which the feet roll over the head (either forward or backward) and return [syn: somersault, somerset, summersault, summerset, somersaulting, flip]

From: GCIDE

Summersault \Sum"mer*sault\, Summerset \Sum"mer*set\, n. See Somersault, Somerset. [1913 Webster]

From: GCIDE

Somersault \Som"er*sault\, Somerset \Som"er*set\, n. [F. soubresaut a jump, leap, OF. soubresault, It. soprassalto an overleap, fr. L. supra over + saltus a leap, fr. salire to leap; or the French may be from Sp. sobresalto a sudden asault, a surprise. See Supra, and Salient.] A leap in which a person turns his heels over his head and lights upon his feet; a turning end over end. [Written also summersault, sommerset, summerset, etc.] "The vaulter's sombersalts." --Donne. [1913 Webster]
Now I'll only Make him break his neck in doing a sommerset. --Beau. & Fl. [1913 Webster]