A Slub Ottoman 3-button Henley T-shirt is a type of shirt made from slub fabric, which has a slightly irregular texture. The term ottoman refers to a ribbed or corded texture often seen in fabrics, which gives it a distinctive appearance. The shirt typically features a Henley neckline, which is a collarless style with a buttoned placket, usually with three buttons. So, this shirt combines the textured look of slub fabric with the ribbed texture of ottoman, along with the casual style of a Henley neckline with three buttons.