twin XL (plural twin XLs)
- (US) A mattress that is slightly longer (usually 38.5 × 79.5 in or 98 × 202 cm) than a twin; a bed designed for such a mattress.
2019 August 31, Alia Wong, “How Twin XL Beds Took Over College Campuses”, in The Atlantic[1]:The twin XL has a twin-size width—helpful given dorm rooms' limited space—and its king-size length, presumably, is a bone thrown to the comfort of students whose bodies are, after all, adult-size. ¶ Twin XLs are so specific to colleges that some families begin the college-preparation process having never heard of the size.
