(from aptus "fit"), the natural disposition any thing hath to serve for such or such a purpose.—Thus, oil hath an aptitude to burn, and water to extinguish fire.

or APTNESSE, is often used, in speaking of the talents of the mind, for a promptitude, or disposition to learn things with ease and expedition. In which sense aptness amounts to the same with what the Greeks call ταχεία, bona indoles, and we sometimes dexterity. Chariton divides aptness into these parts, viz. acuteness, sagacity, and memory.