1. A layer of fibrous tissue. A fascia is a structure of connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, binding some structures together, while permitting others to slide smoothly over each other. (wikipedia.org)
2. The layer of loose tissue, often containing fat, immediately beneath the skin; the stronger layer of connective tissue covering and investing all muscles; an aponeurosis. (wiktionary.org)
3. A thin sheath of fibrous tissue enclosing a muscle or other organ. (Google Dictionary)
4. A sheet or band of fibrous connective tissue separating or binding together muscles and organs etc. (wordnetweb.princeton.edu)
5. The flat layers of fibrous tissue that separate different layers of tissue. A sheet or band of fibrous connective tissue separating or binding together muscles and organs etc. Sheets of connective tissue. (biology-online.org)
Word origin: From Latin fascia (“a band, bandage, swathe”). Related to fascēs (“bundle of rods containing an axe with the blade projecting”), from Proto-Indo-European bʰasko– “band, bundle”.