structural (adj.)

mid-15c., "action or process of building or construction;" 1610s, "that which is constructed, a building or edifice;" from Latin structura "a fitting together, adjustment; a building, mode of building;" figuratively, "arrangement, order," from structus, past participle of struere "to pile, place together, heap up; build, assemble, arrange, make by joining together," related to strues "heap," from PIE *streu-, extended form of root *stere- "to spread."

suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).

1891, from structural + -ism.