noun.
In bot.:
noun.
As used by Linnæus, a leaf, especially the leaf of a palm or fern.
noun.
Now, specifically, a leaf of a fern or other cryptogam, the thallus of a lichen, or any other leaf-like expansion which includes both stem and foliage, as the disk of Lemna.
noun.
In zoology, the foliaceous or leaf-like expansion of certain animal organisms, as of various polyzoans and actinozoans, which resemble plants in the mode of growth of the polypstock.