PE, like Fe, is another Hebrew letter, tho Greek and math people preFer their PI better.
The symbol for the element iron.
The symbol for iron.
A silvery-white, hard metallic element that occurs abundantly in minerals such as hematite, magnetite, pyrite, and ilmenite. It is malleable and ductile, can be magnetized, and rusts readily in moist air. It is used to make steel and other alloys important in construction and manufacturing. Iron is a component of hemoglobin, which allows red blood cells to carry oxygen and carbon dioxide through the body. Atomic number 26; atomic weight 55.845; melting point 1,535°C; boiling point 2,750°C; specific gravity 7.874 (at 20°C); valence 2, 3, 4, 6. See Periodic Table. See Note at element.