Defn: The science of sensation in relation to nervous action. H.
Spenser.

AESTIVAL
Æs"ti*val, a. Etym: [L. aestivalis, aestivus, fr. aestas summer.]

Defn: Of or belonging to the summer; as, æstival diseases. [Spelt also estival.]

AESTIVATE
Æs"ti*vate, v. i. Etym: [L. aestivare, aestivatum.]

1. To spend the summer.

2. (Zoöl.)

Defn: To pass the summer in a state of torpor. [Spelt also estivate.]

AESTIVATION
Æs`ti*va"tion, n.

1. (Zoöl.)

Defn: The state of torpidity induced by the heat and dryness of summer, as in certain snails; — opposed to hibernation.