If something is ornamental, it's a decoration. The red feather in your cap is most definitely ornamental; it serves no purpose other than providing a splash of color.

Ornamental things are, by definition, just for show — they're not actually useful. So an ornamental pond in your yard might be pretty, but you can't fish or swim in it, and an ornamental telephone booth in your friend's living room doesn't really work. Likewise, ornamental plants or gardens are full of beautiful flowers and foliage, but nothing in them is edible.

Definitions of ornamental

adj serving an esthetic rather than a useful purpose

cosmetic, decorative
not having or performing a function

n any plant grown for its beauty or ornamental value

flowering maple
an ornamental plant of the genus Abutilon having leaves that resemble maple leaves
Type of:
flora, plant, plant life
(botany) a living organism lacking the power of locomotion

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