Noah Webster's New International Dictionary of the English Language

1. (v. t.) To rub hard with something rough, as sand or Bristol brick, especially for the purpose of cleaning; to clean by friction; to make clean or bright; to cleanse from grease, dirt, etc., as articles of dress.

2. (v. t.) To purge; as, to scour a horse.

3. (v. t.) To remove by rubbing or cleansing; to sweep along or off; to carry away or remove, as by a current of water; -- often with off or away.

4. (v. t.) To pass swiftly over; to brush along; to traverse or search thoroughly; as, to scour the coast.

5. (v. i.) To clean anything by rubbing.

6. (v. i.) To cleanse anything.

7. (v. i.) To be purged freely; to have a diarrhea.

8. (v. i.) To run swiftly; to rove or range in pursuit or search of something; to scamper.

9. (n.) Diarrhea or dysentery among cattle.