Definition of cramp ball in English:

cramp ball

noun

  • 1†a knar or spherical growth, especially from an oak tree (obsolete rare).

  • 2A variety of inedible ascomycete fungus, Daldinia concentrica (family Xylariaceae), having a hard, spherical black fruiting body; also called King Alfred's cakes.

Origin

Early 20th century; earliest use found in South-eastern Naturalist.