Debouch \De*bouch"\, v. i. [imp. & p. p. {Debouched}; p. pr. & vb. n. {Debouching}.] [F. d['e]boucher; pref. d['e]- (L. dis- or de) + boucher to stop up, fr. bouche mouth, fr. L. bucca the cheek. Cf. {Disembogue}.] To march out from a wood, defile, or other confined spot, into open ground; to issue. Battalions debouching on the plain. --Prescott.