> is the extra layer of indirection in any discipline when things are named after people and not the thing’s characteristics.
"Eigen" in German has same English root as "own": "Eigenvalue" is Germanglish for "Own/inherent value", so meets your spec of naming a thing after its characteristics, as long as "naming" is allowed to be in multiple languages.
How I learnt/taught myself when I first studied this subject, was characteristic or character. People change when they come into money, or rather their character changes (in my head I called them characterless). People with character don't change. Characteristic vector/Eigen vector is something which doesn't change.
"Eigen" in German has same English root as "own": "Eigenvalue" is Germanglish for "Own/inherent value", so meets your spec of naming a thing after its characteristics, as long as "naming" is allowed to be in multiple languages.