S.E.A.

The three-letter acronym SEA could mean:

People/organizations/businesses
SEA Consultants Inc., an engineering consulting firm located in Cambridge, MA.
Scientists and Engineers for America, a pro-science political advocacy group.
Sea Education Association
Service des essences des armées, French army supply corps
Sky Eats Airplane, a digital metalcore band from Texas.
Socialist Environmental Alliance, a minor political party in Northern Ireland.
Società Enti Aeroportuali, the organization running airports in Milan, Italy.
Société d'Études Aéronautiques, the same name given to two different aircraft manufacturers, one French, one Belgian.
Southern Economic Association
State education agency
Students for Environmental Action
System Enhancement Associates, the makers of the Arc file archiver.

Sports teams
 The Seattle Seahawks, a National Football League team
 The Seattle Mariners, a Major League Baseball team
 The Seattle Supersonics, a National Basketball Association team

Mathematical
Schoof-Elkies-Atkin algorithm
Statistical Energy Analysis

Locations
Seattle-Tacoma International Airport (IATA: SEA, ICAO: KSEA)
Southeast Asia

Other
Sky Eats Airplane, a five piece hardcore/electronica group
Search Engine Advertising
Sexual Exploitation and Abuse, a practice common among UN officials working in developing countries
Simplified Email Address
Single European Act
Soluble Egg Antigen
Strategic Environmental Assessment
Stuffit Expander Application
Svensk Elektrobil AB

See also
Sea
Seas