If a word adheres to a certain rule, then I call it a Round Word™.
Use the examples below to find the rule.
|Round Words™||Not Round Words™|
In case you want it in CSV:
Round Words™, Not Round Words™ TEEN, TEXT BUTTON, TENNIS RADIO, CANOE WEIRD, NORMAL MORAL, POWER BASSOON, WOODWIND BATON, BETWEEN NEUTRON, PROTON PHYSICS, POETRY MATH, SCIENCE DEMOTE, CENSURE BAROMETRIC, GEODESIC BEGIN, FINISH TOLD, SAID CAT, DOG
The puzzle relies on the series' inbuilt assumption, that each word can be tested for whether it is a Round Word™ or not on its own.
Clarification (Also a bit of a hint, hence the spoiler format. I went back and forth as to whether you needed to know this):
Most words (including all of the clue words) are definitively Round or Not Round. However, there are some words which could be either, based on the clue words. I call these words Oblong Words™. Your definition of Round might differ slightly from someone else's in whether or not it includes Oblong Words™. Either way is acceptable (as long as it's consistent).
A small hint based on the above:
Here are three Oblong Words™: RAGTAG, VINYL, DERAIL