Entry 1 sense Webster, 1913 Phyllotaxy /(fĭl"lō̇*tăks`y̆)/ · Phyl·lo·tax·y · IPA 01 n. The order or arrangement of leaves on the stem; the science of the relative position of leaves. 1. The order or arrangement of leaves on the stem; the science of the relative position of leaves.(Bot.)