cowl

n. [ AS. cuhle, cugle, cugele; cf. dial. G. kogel, gugel, OF. coule, goule; all fr. LL. cuculla, cucullus, fr. L. cucullus cap, hood; perh. akin to celare to conceal, cella cell. Cf. Cucullate. ] 1. A monk's hood; -- usually attached to the gown. The name was also applied to the hood and garment together. [ 1913 Webster ]

What differ more, you cry, than crown and cowl? Pope. [ 1913 Webster ]

2. A cowl-shaped cap, commonly turning with the wind, used to improve the draft of a chimney, ventilating shaft, etc. [ 1913 Webster ]

3. A wire cap for the smokestack of a locomotive. [ 1913 Webster ]

4. (aviation) a removable metal covering for an aircraft engine, providing streamlining to minimize wind resistance; -- also called cowling. [ PJC ]

5. a covering for a chimney or other ventilating shaft functioning to increase the draft. [ PJC ]