in phonetic translation it's the name of mid-central vowel sound
you can search for the ipa [international phonetic alphabet] table to see it, it's written as ə
its sound is similar to 'a' in about [əˈbaʊt], 'e' in taken [ˈteɪkən], 'i' in pencil [ˈpɛnsəl], 'o' in eloquent [ˈɛləkwənt], 'u' in supply [səˈplaɪ], 'y' in sibyl [ˈsɪbəl]