What is the chemical symbol for iron?

Fe, from the Latin ferrum. The symbols that do not match their English names are the metals known in antiquity - iron, lead as Pb from plumbum, gold as Au from aurum, silver as Ag from argentum, copper as Cu from cuprum, tin as Sn from stannum - all named long before English existed and standardised in Latin by Berzelius in the early 1800s.

Iron is the end of the line in a specific and important sense. Stars fuse light elements into heavier ones and get energy out of it, and that stops at iron: fusing anything heavier consumes energy rather than releasing it. A massive star that has built an iron core has therefore run out of fuel, the core collapses in about a second, and the result is a supernova. Everything heavier than iron in the universe was made in those collapses or in neutron star collisions.

It is also why you are held together. Iron is the atom at the centre of haemoglobin, and its ability to bind oxygen loosely enough to let it go again is what makes blood work - and why blood is red. Rust is the same chemistry running to completion, and the reason iron is abundant on Earth is that a supernova put it here.