D defs.my
Entry 2 senses Webster, 1913

Combust

/kəm-bŭst'/ · Com·bust · IPA /kəmˈbʌst/
01 a. Burnt; consumed.
  1. 1.
    Burnt; consumed.[Obs.]
  2. 2.
    So near the sun as to be obscured or eclipsed by his light, as the moon or planets when not more than eight degrees and a half from the sun.(Astron.) [Obs.]
    “Planets that are oft combust.” Milton.