infradian

== English == === Etymology === Uncertain. Possibly from the Latin infra (“below”) and diēs (“a day”) with the English suffix -an. Compare circadian, ultradian, and infra etc. === Adjective === infradian (not comparable) Cyclical with a periodicity significantly longer than 24 hours, that is, less frequent than circadian. ==== Usage notes ==== The comparative "more infradian" is not used, in contrast to the comparative "more ultradian". === See also === circadian ultradian === Anagrams === Afrindian