1. Geology A thin, leaflike layer or stratum occurring especially in metamorphic rock.
2. Mathematics A plane cubic curve having a single loop, a node, and two ends asymptotic to the same line.
[Latin, leaf; see bhel-3 in the Appendix of Indo-European roots.]
(click for a larger image)folium
The equation of the folium of Descartes is x3 + y3 = 3axy.
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