Many-to-One Lookup Table for taxonomy mapping
I was focused on the effectiveness of my simple solution using CSV files, I didn't consider the obvious-- SQLLite with SQLAlchemy.
I'm working with several ongoing datasets of assets with one or more user applied tag(s) (str) which need to be mapped to one catalog-class (str), each, before importing into a database. Naively I call this 'mapping'.
Lookup Table? Mapping?
The term 'lookup table' has offered more accurate search results, if not a solution. Other terms like mapping, classification, matching are easily confused with other popular problems. My knowledge of LUTs extends to simple Python dictionaries and as the concept in general. Lookup table is what I've used to try to make this a more concrete programming question, but taxonomy mapping is the goal.
If you accept my use of the term mapping in taxonomy mapping, What idioms of mapping, or some other domain solutions can I use for:

many-to-one mapping
decision trees, or weights, or something else to resolve conflicts
validation/audit for mapping rules after updates

I've implemented simpler mapping problems using CSV for storage and management of one-to-one relationships, and simple dict/Pandas DataFrame idioms to get the results I need. I thought for a minute I might do a graphy-like thing, because who doesn't like graphs...