Definition of cramp balls in English:

cramp balls

plural noun

  • A European fungus which produces a shiny spherical black fruiting body on dead or dying wood, especially ash.

    • ‘Of course, even if you've done as I suggest, your cramp balls can be re-infested at a later date unless stored in a bug-proof container.’
    • ‘Dead ash trees are the best places to look for the, shiny fruiting bodies of the fungus Daldinia concentrica, King Alfred's Cakes or cramp balls.’
    • ‘Black cramp balls, or King Alfred's Cakes, pepper the trunk of an old ash.’
    • ‘Certain fungi make very good tinder, in particular; cramp balls and horse's hoof fungus.’
    • ‘Daldinia concentrica also known as King Alfred's cakes, cramp balls or coal fungus is one of the more common species.’

Origin

So named because it was once believed to be a charm against cramp and ague.