I've heard people using both gambo or kruro for leg. Is there a difference between them? Somebody said that maybe one of the two is only from the knee and down. Is this correct?
gamb/o: Tuto de la malsupra membro de homo.
gamb/o: The entire lower member of a human.
And, for kruro
1 Malsupra membro de dupiedulo, antaŭa aŭ malantaŭa membro de kvarpiedulo, aŭ membro de artropodo
2 ❤ (crus) Parto de la malsupra (aŭ malantaŭa) membro de la vertebruloj, inter genuo k piedo
3 Analoga parto ĉe objekto
1 Lower member [limb] of a biped, front or hind member of a quadruped, or a member of an arthropod
2 ❤ (crus) Part of the lower (or hind) member of vertebrates, between knee and foot
3 Analogous part of an object
The ❤ indicates use in biology and histology. So, at least according to PIV, the differences are:
Gambo always refers to the entire lower limb, while kruro in some contexts is only the part between knee and foot.
Gambo is only used for human legs, while kruro can also refer to the legs of animals, arthropods, and objects such as furniture.
I have also noticed that kruro is more commonly used, even for human legs.
Modern dictionaries assert that the kruro is the shank (knee to ankle), at least in medical contexts, while the gambo is the whole leg including the foot.
However, this is a modern distinction and older Esperanto text (all from Zamenhof's time) only uses kruro. I think the Ido word gambo may have been imported by Johannes Dietterle for his visual dictionary but I'm not sure.