(1):

(n.) An instrument or machine for showing when the sun arrived at the tropics and equinoctial line.

(2):

(n.) An instrument for making signals to an observer at a distance, by means of the sun's rays thrown from a mirror.

(3):

(n.) See Bloodstone (a).

(4):

(n.) A plant of the genus Heliotropium; - called also turnsole and girasole. H. Peruvianum is the commonly cultivated species with fragrant flowers.