ob-stācŭlum, i, n. [obsto], a hinderance, obstacle (post-class.; cf. impedimentum): teneris et rarioribus parcit (fulmen), quia transitu patente minus obstaculum invenit, Sen. Q. N. 2, 52, 1: rumpere obstacula, Prud. Ham. 601; App. Flor. p. 361, 11; Arn. 2, 62; Amm. 17, 3.
In plur., of mountains, Amm. 21, 10.