Vestigial
A biological term used for organs or structures in an organism that have lost most or all of their original function through evolution.
These are remnants from a past ancestor that no longer serve a purpose in the current form of the organism. Examples include the human appendix, the wings of flightless birds, or the pelvic bones of snakes.
Residual
A more general term meaning “remaining” or “left over” from something else. It can be used in various contexts, not just biological.
For instance, “residual chemicals” might be leftover substances after a process, or “residual income” could be earnings you receive without actively working.
Summary
| Term | Context | Meaning | Example |
|---|---|---|---|
| Vestigial | Biology | Organs or structures that have lost their original function through evolution | The human appendix |
| Residual | General | Something that remains or is left over | Residual stains on a carpet |