vestigial

Everyday

1. (science) Describing a part of a body that is still there but has become small or useless over a very long time, such as the tiny leg bones inside some snakes. tree →
2. (formal) Remaining as a small trace or bit of something that used to be bigger or more important. tree →

In the lessons

In science lessons about evolution, vestigial body parts are clues that living things changed over a long time. Examples often given are the tailbone in humans, the wings of birds that cannot fly (like the ostrich and kiwi), and leg bones in whales. Phrases: "a vestigial organ", "vestigial wings", "a vestigial tail".

Examples

• Ostriches have vestigial wings that cannot lift them into the air. tree →
• Whales have small vestigial leg bones inside their bodies. tree →
• The human tailbone is often called a vestigial part. tree →
• The kiwi has tiny vestigial wings hidden under its feathers. tree →
• Scientists study vestigial organs to learn how animals changed. tree →
• Only a vestigial bit of the old castle wall is left. tree →

Note

Adjective, from "vestige" (a small trace that remains). Pronounced vest-IJ-ee-ul. Myth trap: "vestigial" does not always mean completely useless; some vestigial parts, like the human appendix and tailbone, still have small uses. It is a science and formal word.