- A substance that oxidizes another substance, especially one that supports the combustion of fuel; an oxidizing agent.
- That which oxidizes.
- An agent employed in oxidation, or which facilitates or brings about combination with oxygen
- An <xref>oxidizing agent</xref>, especially one used to <xref>oxidize</xref> the <xref>fuel</xref> of a <xref>rocket</xref> or a <xref>fuel cell</xref>.
- a substance that oxidizes another substance