the number equivalent to the product of three and ten; ten less than forty; 30:thirty or forty years agothirty were hurtthirty of her school friends (Roman numeral: xxx, XXX)
(thirties) the numbers from thirty to thirty-nine, especially the years of a century or of a person’s life:a woman in her thirtiesshe was a famous actress in the thirties
thirty years old:I’ve got a long way to go before I’m thirty
Old Englishthrītig(see three, -ty2). The spelling with initial thi- is recorded in the 15th century, and has been the prevalent form since the 16th century
