What is the definition or description of: subcutaneous?

See below: The hypodermis, also called the hypoderm, subcutaneous tissue, subcutis, or superficial fascia, is the lowermost layer of the integumentary system in vertebrates. Types of cells that are found in the hypodermis are fibroblasts, adipose cells, and macrophages. It is derived from the mesoderm, but unlike the dermis, it is not derived from the dermatome region of the mesoderm.

Subcutaneous.: Under the skin, as opposed to within or atop the skin.