Ett or ETT may refer to: Arts Caspar Ett (1788–1847), German composer and organist English Touring Theatre Mathematics Euler tour technique, in graph theory Extensional type theory, in logic Medicine Endotracheal tube, in respiratory medicine Epithelioid trophoblastic tumour, a very rare cancer Ergothioneine transporter, a protein and human gene (SLC22A4) Exercise Tolerance Test, in cardiology Military Embedded Training Teams in Afghanistan EBR ETT, a French armoured personnel carrier Other uses Elementary Teachers of Toronto, a Canadian labour union English Toy Terrier, a dog breed Etruscan language, once spoken in Italy (ISO 639-3: ett) European Transactions on Telecommunications, a scientific journal