T-shirt; tee shirt
Standard loanword for a short-sleeved casual top, exactly like English 'T-shirt'.
I'm wearing a white T-shirt today.
It was hot, so I wore a white T-shirt.
Where did you buy that T-shirt?
汗をかいたのでTシャツを脱いだ。
I was sweaty, so I took off my T-shirt.
He always goes out wearing just a T-shirt.
Tシャツ is typically counted with 枚 as a thin, flat garment.
Tシャツ can also be counted with 着 when emphasizing it as a full item of clothing.
Loanword from English 'T-shirt', referring to the T-like shape of the garment.