Dyke (normal International spelling) or Dike (normal American spelling) can mean several things:

• A dyke / dike is a long wall built to keep out the sea or enclose land.
• Dyke / Dike is another word for a ditch
• Dyke / Dike is a slang term for a lesbian.
• In geology, a dyke / dike is a long mass of minerals, usually an intrusion of igneous rocks, filling up rents or fissures in the original strata.
• Dike is the Greek goddess of moral justice.
• 99 Dike is an asteroid.