The Collaborative International Dictionary of English v.0.48:

Offshoot \Off"shoot`\, n. [Off + shoot.]
   That which shoots off or separates from a main stem, channel,
   family, race, etc.; as, the offshoots of a tree.
   [1913 Webster]

WordNet (r) 3.0 (2006):

offshoot
    n 1: a natural consequence of development [syn: outgrowth,
         branch, offshoot, offset]