smichr/sympy — comment on commit 1e2b8409c4c390f65fdc77e2b36a93bd2f43ea0b
File:  line 0
By pernici:

"principal root" is more common than "principle root";
grepping one can see that almost everywhere in sympy one uses the former, or the related "principal branch";
only three times the latter is used, maybe it could be changed to "principal" also there.