If you want to import taxonomy terms ... then this module, along with Hierarchical Taxonomy Import, is the solution. You can, using a CSV, import all terms with it.
If you have hierarchical terms (see below), you can use this module too.
You must then use two columns. The first row has labels. The 'Parent' comes after the 'Child' term. You can not assign a Parent that has not been created yet. Line 2 and 3 in the example show that I created the parents before I import the rest. You can also do this with a separate import.
Because in my example, some street names have different parents (eg Kerkstraat occurs in many municipalities as street) you must install a patch at the time of this writing. (See link)
After that it is a piece of cake..