Most creatures known as sea slugs are actually snails, i.e. they are sea snails (marine gastropod mollusks) that over evolutionary time have lost their shells, or have a greatly reduced shell or an internal shell. sea cucumber also looks slug-like and is sometimes loosely called a sea slug, but it is not a gastropod. Sea slug is a common name which is applied to some marine invertebrates that more or less resemble terrestrial slugs.
Medical Definition of VERTEBRA. : any of the bony or cartilaginous segments that make up the spinal column and that have a short more or less cylindrical body whose ends articulate by pads of elastic or cartilaginous tissue with those of adjacent vertebrae and a bony arch that encloses the spinal cord.ord Root of VERTEBRA. The Latin word vertere, meaning â to turn â or â to change, â and its form versus give us the roots vert and vers. Words from the Latin vertere have something to do with turning or changing.
1 Anatomy[Anat.]the spinal column; spine. 2  strength of character; resolution. 3  something resembling a backbone in appearance, position, or function. 4  Printing[Bookbinding.]a back or bound edge of a book; spine.