Methane oxidation is the conversion of CH₄ to a more oxidized carbon product—methanol, CO, CO₂, or biomass carbon—by transfer of oxygen atoms and/or electrons to the methane carbon. In catalysis and oxidation reactions the concept is bounded by methane as the substrate and by a net increase in the oxidation state of that carbon. Essential features are activation of the inert C–H bond, an oxidant (O₂, a metal-oxo, nitrite, or a metal ion), and a pathway that determines whether the carbon stops at a partially oxidized product or proceeds to CO₂. Anaerobic methane oxidation couples CH₄ oxidation to denitrification or to the reduction of manganese or iron, so that oxygen in the formal sense need not be the terminal electron acceptor ^[1][2][3]. Aerobic methanotrophy uses O₂ to hydroxylate methane at a metalloenzyme, including in extremely acidophilic Verrucomicrobia ^[4]. Nitrogen species can regulate the same oxidation in soils and sediments by competing at the methane-activating enzyme or by supplying an alternative electron acceptor ^[1][2]. The concept is distinguished from methane pyrolysis, which does not raise the carbon oxidation state by oxygen-atom or electron-acceptor coupling, and from Fischer–Tropsch chemistry, which builds C–C bonds from CO rather than oxidizing CH₄. Conceptual limits exclude combustion descriptions that omit the catalytic or enzymatic C–H activation step as the defining event.