T-shirt
noun
ˈtē-ˌshərt 
variants or less commonly tee shirt
: a collarless short-sleeved or sleeveless usually cotton undershirt
also : an outer shirt of similar design
T-shirted
ˈtē-ˌshər-təd
adjective 
Word History
First Known Use
1920, in the meaning defined above
Kids Definition
T-shirt
noun
variants also tee shirt
ˈtē-ˌshərt
: a shirt with short sleeves and no collar and usually made of cotton