ox·i·dize / ˈäksiˌdīz/ • v. combine or become combined chemically with oxygen: [tr.] when coal is burned any sulfur is oxidized to sulfur dioxide | [intr.] the fats in the food will oxidize, turning it rancid. ∎ Chem. undergo or cause to undergo a reaction in which electrons are lost to another species. The opposite of reduce.DERIVATIVES: ox·i·diz·a·ble adj.ox·i·di·za·tion / ˌäksidiˈzāshən/ n.ox·i·diz·er n.