Earlier quoted context omitted.
George Lucas was inspired by samurai films. This film are called jidai seki (period films). From jidai --> jedi. Also C3PO and R2D2 are inspired by the couple of mongrels in Hidden Fortress.
This is also why the Jedi (at least in the earlier films) use two hands to hold their lightsabers. It's the Japanese style. Of course, Samurai swords were two-handed because they were heavy, due to the poor quality of steel available. A light saber "blade" would presumably weigh nothing, so it would make more sense to hold it one handed like a, well, saber. A master of the more technologically advanced European saber…
It just depends on context and skill.