1. a leaf of a plant, especially when considered in botanical or scientific contexts
Usage: botanical; technical
2. a thin leaflike part or layer of rock or mineral
Usage: geological
3. a leaf of a book or manuscript
Usage: archaic; literary

Examples

• The botanist examined each folium under the microscope.
• The specimen showed clear folium structure typical of deciduous trees.
• Geologists identified distinct folia in the metamorphic rock sample.
• The ancient manuscript’s folia were carefully preserved.
• Each folium of the medieval text contained illuminated letters.
• The rock’s foliated structure revealed multiple thin folia.