Folium (, "leaf"), plural folia, may refer to * a leaf of a book: see

recto and verso ''Recto'' is the "right" or "front" side and ''verso'' is the "left" or "back" side when text is written or printed on a leaf of paper () in a bound item such as a codex, book, broadsheet, or pamphlet. In double-sided printing, each leaf h ...

Folium of Descartes In geometry, the folium of Descartes (; named for René Descartes) is an algebraic curve defined by the implicit equation x^3+y^3-3a\cdot xy=0. dy/dx=(x^2-ay)/(ax-y^2), \,dx/dy=(ax-y^2)/(x^2-ay). History The curve was first proposed and studi ...

, an algebraic curve * Folium (spider), a marking on the abdomen of a spider

Brain anatomy

Folium (brain) The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or eve ...

* Folium vermis

Botany

Turnsole Turnsole, katasol, or folium was a dyestuff prepared from the annual plant ''Chrozophora tinctoria''. History Turnsole became a mainstay of medieval Illuminated manuscript, manuscript illuminators starting with the development of the technique fo ...

or folium, a dyestuff * Folium Phyllostachydis, processed leaves of bamboo * Hydrangeae Dulcis Folium, processed leaves of hydrangea {{disambig