welter

As a verb walter

is (obsolete|dialect|uk|scotland) to roll or wallow; to welter.

As a noun welter is

welter (boxing class).

As nouns the difference between welter and helter

is that welter is welter (boxing class) while helter is (northern england|obsolete).

As nouns the difference between taxonomy and welter

is that taxonomy is the science or the technique used to make a classification while welter is welter (boxing class).