A spherical pressure vessel used for the storage of compressed volatile gases in a liquid and gaseous state such as hydrocarbons and fuel gases. A trademark name registered by the Chicago Bridge and Iron Company (CBI), it is named in honour of the American bridge designer Horace Ebenezer Horton who founded the company in 1889.

http://www.cbi.com/about-cbi/history/ Official website of the Chicago Bridge and Iron Company.