architectural (adj.)

1560s, "the art of building," especially of fine or beautiful building; "tasteful application of scientific and traditional rules of good construction to the materials at hand," from French architecture, from Latin architectura, from architectus "master builder, chief workman" (see architect). The meaning "buildings constructed architecturally" is from 1610s.

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)).