from
The Collaborative International Dictionary of English v.0.48
Endorse \En*dorse"\, v. t. [imp. & p. p. {Endorsed}; p. pr. &
vb. n. {Endorsing}.] [Formerly endosse, fr. F. endosser to
put on the back, to endorse; pref. en- (L. in) + dos back, L.
dorsum. See {Dorsal}, and cf. {Indorse}.]
Same as {Indorse}.
[1913 Webster]
Note: Both endorse and indorse are used by good writers; but
the tendency is to the more general use of indorse and
its derivatives indorsee, indorser, and indorsement.
[1913 Webster]