oxo in English dictionary oxo Meanings and definitions of "oxo" (chemistry, in combination) A substituent oxygen atom connected to another atom by a double bond the game noughts and crosses noun (chemistry, in combination) A substituent oxygen atom connected to another atom by a double bond noun the game noughts and crosses more Grammar and declension of oxo oxo ( plural oxos) oxo (uncountable) more OXO Oxo Sample sentences with "oxo" Declension Stem Try again Available translations Catalan French German Italian Polish Romanian Spanish Turkish Authors