Schwa

In linguistics, specifically phonetics and phonology, schwa (sometimes spelled shwa) refers to the mid-central vowel sound (rounded or unrounded) in the middle of the vowel chart, denoted by the IPA symbol ə, or another vowel sound close to that position. An example in English is the vowel sound in the second syllable of the word sofa. Schwa in English is limited to unstressed positions, but in some other languages it can occur as a stressed vowel.