The compound adjective 'spiral-bound' is a modern descriptive term from the 20th century, created to specify a particular bookbinding method. The first element, 'spiral', traces back to the Latin spira, meaning a coil or twist, which entered English via Medieval Latin and French to describe a continuous curve winding around a central point. The second element, 'bound', originates from the Old English verb bindan, a common Germanic root meaning to tie or make fast. Combined, the term literally and logically describes an object whose pages are 'fastened by a coil', directly linking the physical mechanism (a wire or plastic spiral) to the functional result (a bound book that lies flat).

Structure: spiral (coil) + bound (fastened) - spiral: From Latin spiralis (coiling), from spira (coil). A noun/adjective used attributively here to describe the type of fastener. - bound: From Old English bindan (to tie). A past participle used in a compound adjective to mean 'fastened' or 'secured'.