Definition of nyctitropism in US English:
nyctitropism
Origin
Late 19th century; earliest use found in Charles Darwin (1809–1882), naturalist, geologist, and originator of the theory of natural selection. From nycti- + -tropism.
Pronunciation
nyctitropism
/ˌnɪktɪˈtrəʊpɪz(ə)m/