The Collaborative International Dictionary of English v.0.48:

Determinative \De*ter"mi*na*tive\, a. [Cf. F. d['e]terminatif.]
   Having power to determine; limiting; shaping; directing;
   conclusive.
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         Incidents . . . determinative of their course. --I.
                                                  Taylor.
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   Determinative tables (Nat. Hist.), tables presenting the
      specific character of minerals, plants, etc., to assist in
      determining the species to which a specimen belongs.
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