(1) (botany) The arrangement of petals (as well as sepals) within a flower bud that is yet to open.
(2) (zoology) The lack of or slowing of activity and metabolism during hot, dry season such as summer; summer dormancy; prolonged and deep torpor during the hot, dry season.
In botany, aestivation may be valvate, imbricate, plicate, or contorted.
In zoology, while hibernation refers to dormancy during the cold season, aestivation pertains to a state where some animals go through dormancy or lack of activity during the warm, arid season.
Word origin: Latin aestivare, from aestus, (heat).
Related form(s): aestivate (verb)