Definition of auxin
1 : any of various usually acidic organic substances that promote cell elongation in plant shoots and usually regulate other growth processes (such as root initiation): such asa : indoleacetic acidb : any of various synthetic substances (such as 2,4-D) resembling indoleacetic acid in activity and used especially in research and agriculture
2 : plant hormone
auxinicplay \ȯk-ˈsi-nik\ adjective
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