fi·brous \ˈfībrəs\adjective Etymology: French fibreux, from fibre fiber (from Latin fibra) + -eux -ous 1. a.: containing, consisting of, or like fibers < fibrous roots > < the fibrous husk of a coconut > < fibrous proteins > b.: characterized by fibrosis c.: capable of being separated into fibers < a fibrous mineral > also: breaking in a manner that exposes needlelike grains 2.: possessing body, strength, or toughness : sinewy, hardened • fi·brous·lyadverb • fi·brous·nessnoun-es