An incrustation over a sore, wound, vesicle, or pustule, formed by the drying up of the discharge from the diseased part.
- A crust discharged from and covering a healing wound.
- Scabies or mange in domestic animals or livestock, especially sheep.
- Any of various plant diseases caused by fungi or bacteria and resulting in crustlike spots on fruit, leaves, or roots.
- The spots caused by such a disease.
- Slang A person regarded as contemptible.
- A worker who refuses membership in a labor union.
- An employee who works while others are on strike; a strikebreaker.
- A person hired to replace a striking worker.
- To become covered with scabs or a scab.
- To work or take a job as a scab.