[1] Electronic Tandem Switch(ing)

[2] European Telephone System

[3] Electronic Translator System

[4] Ethernet Terminal Server

[5] European Telecommunications Standard (of ETSI)

[6] Executable Test Suite

[7] External Transaction Services

[8] Electronic Telegraph System (->"IEEE Standard Dictionary")

[9] Electrical Test Set (->"NASA Acronym List")

[10] Energy Transfer System (->"NASA Acronym List")

[11] External Tank (Sub-)System (->"NASA Acronym List")

[12] Enterprise, AL, USA -internationale Fughafen-Kennung