Astron. Chiefly pl. faculæ. [L. facula, dim. of fac-em, fax torch.] One of the bright or luminous spots or streaks on the surface of the sun, as distinguished from the dark spots or maculæ.
1706. Phillips (ed. Kersey), Facula, a little Torch: Among Modern Astronomers, Faculæ, are certain Bright or Shining Parts, which they have sometimes observed upon, or about the Surface of the Sun.
1794. Sullivan, View Nat., II. 415. When they [solar spots] disappear, they are generally converted into faculæ or luminous spots, which appear much brighter than the rest of the sun.
1858. Herschel, Outlines Astron. (ed. 5), § 388. Strongly marked … streaks, more luminous than the rest, called faculæ.
1881. Stokes, in Nature, No. 625. 595. Sometimes faculæ will break out at the surface of the sun where there is no spot.
