Definify.com

Webster 1913 Edition

{

(fĭl′lō̍-tăksˊy̆)

(fĭl′lō̍-tăksˊĭs)

, }

Noun.

[

Phyllo-

+ Gr.

τάξισ

order.]

(Bot.)

The order or arrangement of leaves on the stem; the science of the relative position of leaves.

phyllotaxis ‎(usually uncountable, plural phyllotaxes)

(botany) The arrangement of leaves on a stem, or the mathematical principles governing such arrangement.
- 1985, John Fowles, A Maggot:
  Yet his Lordship would find this rate of proportion […] likewise in all plants, in the disposition of their leaves, for which ordering he would make a name, that is, from the Greek, phyllotaxis.

The arrangement of leaves on a stem