T-back; thong; bikini thong
A garment, especially underwear or swimwear, whose back part is narrow or T-shaped like a thong. Not vulgar, but the topic can be intimate or clothing-specific.
This swimsuit has a T-back at the back.
She was wearing a thong at the beach.
T-back underwear is less likely to show panty lines.
There was a photo of her in a thong printed in the magazine.
As underwear or swimwear, Tバック (thong) is typically counted with 枚.
Attested spelling using a full-width Latin Ｔ plus katakana; used for thong-style underwear or swimwear.
Practical typographic variant using an ASCII T; common in digital writing, though the form uses full-width Ｔ.
The spelling combines the Latin letter T with バック, reflecting the T-shaped back of the garment. No language of origin is specified.