simultaneous reactions
composite reactions, in which processes like \[\text{A}\ \overset{1}{\rightarrow }\ \text{Y}\] and \[\text{B}\ \overset{2}{\rightarrow }\ \text{Z}\] occur in parallel, can be called simultaneous or parallel reactions. Sometimes there is competition involved, like in the scheme: \[\text{A}\,+\,\text{B}\ \overset{1}{\rightarrow }\ \text{Y}\] and \[\text{A}\,+\,\text{C}\ \overset{2}{\rightarrow }\ \text{Z}\] where B and C compete with one another for A.
PAC, 1993, 65, 2291. 'Nomenclature of kinetic methods of analysis (IUPAC Recommendations 1993)' on page 2297 (