means A decorative object or detail added to something purely to make it more beautiful, serving no practical purpose.

from From Latin 'ornamentum' (equipment, adornment), from the verb 'ornare' meaning 'to equip, fit out, embellish' — the same root that gives us 'adorn' and 'ornate.' Interestingly, 'ornare' first meant something closer to 'to make ready' or 'furnish'; the leap from practical equipping to pure decoration happened along the way, as if the Romans themselves couldn't resist a little extra flourish. It reached English through Old French 'ornement' in the medieval period.