Definition of rheotaxis in US English:

rheotaxis

noun

Biology
  • The directed movement of a motile cell or organism in response to a current of water (or occasionally air); an instance of this.

Origin

Late 19th century. From rheo- + -taxis, after German Rheotaxis.

Pronunciation

rheotaxis

/ˌriːə(ʊ)ˈtaksɪs/