There are other words with less letters. The ones that we recognize as commonly-known words are:
aorta, aviator, grain, grant, groan, groin, intro, orating, organ, rating, ratio, ration, raving, roving, tiara, train, vagrant, variant, and vigor.
That’s 19 words, but the English dictionary recognizes up to 39 words total. Can you find all of them?