The word 'tactual' is a modern adjective formed directly from the Latin root for touch. Its core, 'tact-', originates from the Latin verb tangere, meaning "to touch," which itself is traced back to the Proto-Indo-European root tag-, also meaning "to touch, handle." The suffix '-ual', descending from Latin -alis, is a common adjectival ending in English. Therefore, 'tactual' follows a clear and logical construction: it literally means "of or pertaining to touch," a meaning it retains in its modern, specialized use primarily in psychological and physiological contexts to describe sensations or perceptions received through the skin.

Structure: tact (touch) + ual (adjective suffix) - tact: From Latin tactus (touch, sense of touch), from the verb tangere (to touch). It functions as the core root conveying the sense of touch. - ual: A suffix of Latin origin (-alis), used to form adjectives meaning "of, relating to, or characterized by."