"narrow channel of water" in a river, etc., 1630s, plural of narrow (n.). Meaning "narrow passage through a mountain" is from 1716.
Old English nearolice "with little breadth or extent, closely; strictly; carefully;" see narrow (adj.) + -ly (2). Meaning "only by a little, by a small distance" is attested from 1550s.
also narrowminded, "bigoted, illiberal, of confined views or sentiments," 1620s, from narrow (adj.) + -minded. Related: Narrow-mindedness. Middle English had narrow-hearted "mean, ungenerous, ignoble" (c. 1200).
"quality or condition of being narrow," Middle English narwenesse, from Old English nearuness "narrowness" also "constraint, distress;" see narrow (adj.) + -ness.