taxis
n. C / Un. the movement of a tiny living thing, like a cell or insect, toward or away from something in its environment. This could be a movement toward light, heat, or a specific chemical.
n. the directional movement of a motile organism or cell in response to an external stimulus. The movement is classified as positive if it is toward the stimulus and negative if it is away from it.
The bacteria show positive taxis toward the sugar source.
Learned borrowing from Ancient Greek τάξις (táxis, “arrangement, order”).
See taxi.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Usage
Often appears as a suffix in scientific terms like 'phototaxis' or 'chemotaxis'.
Last updated May 6, 2026