“Earl” is a reflex of the *h3er root discussed briefly in this article (it remained distinct in Germanic and is likely also the source of the noun *erō, “battle”, so an *er-ilaz is a “war leader”.
“Hero” is slightly more opaque but appears to descend from a roof *ser- meaning “bind, tie” with an extended meaning “capture.” A “hero” is therefore one who captures either riches or slaves in a raid.
I wonder where the Greek "hero" or the Germanic "Earl/Jarl" are related.
“Earl” is a reflex of the *h3er root discussed briefly in this article (it remained distinct in Germanic and is likely also the source of the noun *erō, “battle”, so an *er-ilaz is a “war leader”.
“Hero” is slightly more opaque but appears to descend from a roof *ser- meaning “bind, tie” with an extended meaning “capture.” A “hero” is therefore one who captures either riches or slaves in a raid.