Share this entry
infradian Line breaks: in|fra|dian
Pronunciation: /ɪnˈfreɪdɪən/

Definition of infradian in English:


(Of a rhythm or cycle) having a period of recurrence longer than a day; occurring less than once a day. Compare with ultradian.
Example sentences
  • The crayfish Procambarus clarkii is a nocturnal organism that displays a span of overt circadian and infradian rhythms to adapt to daily and seasonal environmental lighting changes.
  • The circadian rhythm resides with an infradian rhythm of lunar 28-day cycles, seasonal cycles of cold and hot as well as shifting light and dark.
  • In this paper, a presumptive role for infradian hormonal rhythms is considered.


Mid 20th century: from infra- 'below' (i.e. expressing a lower frequency), on the pattern of circadian.

Definition of infradian in:
Share this entry

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.

Subscribe to remove ads and access premium resources