D defs.my
Entry 3 senses Webster, 1913

Asterism

/(-ĭz'm)/ · As·ter·ism · IPA /ˈæs.təˌrɪz.əm/
01 n. A constellation.
  1. 1.
    A constellation.(Astron.) [Obs.]
  2. 2.
    An asterisk, or mark of reference.(Printing) [R.]
  3. 3.
    An optical property of some crystals which exhibit a star-shaped by reflected light, as star sapphire, or by transmitted light, as some mica.(Crystallog.)