The Collaborative International Dictionary of English v.0.48:

Insition \In*si"tion\ (?; 277), n. [L. insitio, fr. inserere,
   insitum, to sow or plant in, to ingraft; pref. in- in +
   serere, satum, to sow.]
   The insertion of a scion in a stock; ingraftment. --Ray.
   [1913 Webster]