: a tissue of mesodermal origin that consists of various cells (such as fibroblasts and macrophages) and interlacing protein fibers (as of collagen) embedded in a chiefly carbohydrate ground substance, that supports, ensheathes, and binds together other tissues, and that includes loose and dense forms (such as adipose tissue, tendons, ligaments, and aponeuroses) and specialized forms (such as cartilage and bone)