Scab can refer to the following:

• The crust covering a healing wound as a result of coagulation.
• A slang term for a strike-breaker. Also electronic scabbing, when computer networks are used to transfer work from a striking workforce to a non-striking one.
• Various animal and plant diseases, including:
  • Fusarium head blight, a fungus disease found on small grain crops such as wheat.
  • The scab disease in sheep, caused by attack by the sheep scab mite (Psoroptes ovis).
  • A common skin disfigurement in the potato
  • Black scab, a serious fungal infection of the potato
• Various Danish organizations have names ending in -skab. This is the Danish equivalent of the "-ship" suffix in "fellowship" and "friendship" etc, and has no connection with the English word "scab".

costra