The Collaborative International Dictionary of English v.0.48:
Behead \Be*head"\, v. t. [imp. & p. p. Beheaded; p. pr. & vb. n. Beheading.] [OE. bihefden, AS. behe['a]fdian; pref. be- + he['a]fod head. See Head.] To sever the head from; to take off the head of. [1913 Webster]WordNet (r) 3.0 (2006):
beheading n 1: execution by cutting off the victim's head [syn: decapitation, beheading] 2: killing by cutting off the head [syn: decapitation, beheading]