Mid vowel

A mid vowel (or a true-mid vowel) is a class of vowels used in some spoken languages. The tongue is placed midway between an open vowel and a close vowel.
Other names are lowered close-mid vowel and raised open-mid vowel. The first phrase may be used to describe a vowel as low as open-mid. And the other one could also be used to describe a vowel as high as close-mid.