Encyclopedias, Almanacs, Transcripts, and Maps
- Seaton, John Colborne, 1st Baron
- seawall
- Seba
- Sebago Lake
- Sebald, W. G.
- Sebaste
- Sebastopol
- Sebat
- Secaucus
- Secession, War of
- Second Adventists
- Second Shepherds' Play
- Secord, Laura (Ingersoll)
- secret society
- Secretariat, United Nations
- Securities and Commodities Markets
- securities trading
- Sedgwick, Ellery
- Sedgwick, Theodore
- Sedna