Definition of infradian in English:

Share this entry


Pronunciation: /ɪnˈfreɪdɪən/


(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.

For editors and proofreaders

Line breaks: in|fra|dian

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.