magnet

The whole family starts with a place, not a thing. In ancient times there was a region in Asia Minor called Magnesia, and the rocks dug up there had an eerie property: they pulled iron toward themselves without being touched. The Greeks called such a rock magnēs lithos — literally 'the Magnesian stone.' Over time people dropped 'lithos' and the place name alone, magnēs, came to mean the stone, and then the mysterious attracting power inside it. That is how a spot on a map became the English word magnet.

From this single image — a stone that reaches out and grabs iron — the family grows in two directions, the literal and the figurative.

The literal branch is physics. Add the adjective ending and you get magnetic, 'having the pull of the Magnesian stone': a magnetic field, a magnetic needle. Turn the property into a noun with -ism and you get magnetism, the force itself. Make it a verb with -ize and you get magnetize, 'to give something the power of the stone' — to magnetize a needle by stroking it. Put de- ('off, away') in front and you reverse the process: demagnetize, to strip that power out, to wipe a tape or a magnetic strip clean.

Then science discovered the force had relatives. Run electricity through a coil and it behaves like a magnet — so electric + magnetic gave electromagnetic, 'where electricity makes magnetism.' Some metals, iron above all, can be magnetized strongly and keep it; from Latin ferrum ('iron') plus magnetic came ferromagnetic, 'iron-strongly-magnetic.' And the planets turned out to carry magnetism too: a planet is wrapped in a magnetosphere (magnet + sphere), the invisible magnetic shell that deflects the solar wind.

The figurative branch is about people. A person who draws others irresistibly is described with the very same words: a magnetic personality, full of personal magnetism. A charismatic speaker can magnetize an audience — hold a whole room the way the Magnesian stone held iron filings. English never invented a separate word for human charm here; it simply reused the physics, because the picture is the same: something that pulls others in without effort.

One footnote worth knowing: Magnesia was generous with names. The same region also gave us magnesium and manganese, two metals — so when you see those words, remember they are geographic cousins of magnet, not chemical relatives of magnetic force. And the old English word for a natural magnet, lodestone ('leading stone,' because sailors used it to find north), is a pure synonym for the original magnēs lithos.