Noun
(fluid dynamics) A shock wave formed by the bow of an object travelling at supersonic speed.
(astronomy) The region of the magnetosphere in which the solar wind slows from supersonic to subsonic.
A bow wave.
Source: en.wiktionary.orgBow shock Infrared image and artist's concept of the bow shock around R Hydrae main The bow shock forms the outermost layer of the magnetosphere; the boundary between the magnetosphere and the ambient medium. Source: Internet