1. The final or conclusive stage of a process, development, or condition where the outcome is determined and established
The company entered the definitive phase of the merger negotiations.
A empresa entrou na fase definitiva das negociações de fusão.
2. In biology/parasitology: the stage in an organism's life cycle where it reaches its final form or where reproduction occurs in the host
The parasite reaches its definitive phase in the human host.
O parasita atinge sua fase definitiva no hospedeiro humano.
3. In legal or administrative contexts: the binding or final stage of a procedure
The contract entered its definitive phase after all parties signed.
O contrato entrou em sua fase definitiva após a assinatura de todas as partes.