low vowel vs open vowel

low vowel and open vowel both are nouns.

Word	Noun	Adjective	Verb	Adverb
low vowel	Yes	No	No	No
open vowel	Yes	No	No	No

As nouns, low vowel and open vowel are synonyms defined as:

low vowel and open vowel: a vowel that you pronounce with your tongue on the bottom of your mouth.

low vowel (noun)	open vowel (noun)
a vowel that you pronounce with your tongue on the bottom of your mouth.	a vowel that you pronounce with your tongue on the bottom of your mouth.