What's the noun for turtlebacks? Here's the word you're looking for.
turtle
(US, Canada) Any land or marine reptile of the order Testudines, characterised by a protective shell enclosing its body. See also tortoise.
(Australia, Britain) A marine reptile of that order; a sea turtle.
(military) An Ancient Roman attack method, where the shields held by the soldiers hide them, not only left, right, front and back, but also from above.
(computing) A type of robot having a domed case (and so resembling the reptile), used in education, especially for making line drawings by means of a computer program.
(computing) An on-screencursor that serves the same function as a turtle for drawing.
(printing, historical) The curved plate in which the form is held in a type-revolving cylinder press.
(computing theory) A small element towards the end of a list of items to be bubble sorted, and thus tending to take a long time to be swapped into its correct position. Compare rabbit.
A breakdancingmove consisting of a float during which the dancer's weight shifts from one hand to the other, producing rotation or a circular "walk".