infradian
Syllabification: (in·fra·di·an)
Pronunciation: /inˈfrādēən/
Definition of infradian
adjective
Physiology- (of a rhythm or cycle) having a period of recurrence longer than a day; occurring less than once a day. Compare with ultradian.
Origin:
mid 20th century: from infra- 'below' (i.e., expressing a lower frequency), on the pattern of circadian