Open-mid front unrounded vowel
The open-mid front unrounded vowel, or low-mid front unrounded vowel, is a type of vowel sound used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is the Latin epsilon, a Latinized variant of the Greek lowercase epsilon, ⟨ɛ⟩.
Source: Wikipedia — Open-mid front unrounded vowel (CC BY-SA 4.0)