Teos or Teo was an ancient Greek city on the coast of Ionia, on a peninsula between Chytrium and Myonnesus. It was founded by Minyans from Orchomenus, Ionians and Boeotians, but the date of its foundation is unknown. Teos was one of the twelve cities which formed the Ionian League. The city was situated on a low hilly isthmus. Its ruins are located to the south of the modern town Sigacik in the Seferihisar district of Izmir Province, Turkey.

Tetraethyl orthosilicate is the chemical compound with the formula Si(OC₂H₅)₄. Often abbreviated TEOS, it is a colorless liquid that degrades in water. TEOS is the ethyl ester of orthosilicic acid, Si(OH)₄. It is a prototypical alkoxide.

Teos or Teo was an ancient Greek city on the coast of Ionia, on a peninsula between Chytrium and Myonnesus. It was founded by Minyans from Orchomenus, Ionians and Boeotians, but the date of its foundation is unknown. Teos was one of the twelve cities which formed the Ionian League. The city was situated on a low hilly isthmus. Its ruins are located to the south of the modern town Sigacik in the Seferihisar district of Izmir Province, Turkey.

Tetraethyl orthosilicate is the chemical compound with the formula Si(OC₂H₅)₄. Often abbreviated TEOS, it is a colorless liquid that degrades in water. TEOS is the ethyl ester of orthosilicic acid, Si(OH)₄. It is a prototypical alkoxide.