"schwa"
The schwa is the vowel sound in many lightly pronounced unaccented syllables in words of more than one syllable. It is sometimes signified by the pronunciation "uh" or symbolized by an upside-down rotated e.
The a is schwa in adept.
The e is schwa in synthesis.
The i is schwa in decimal.
The o is schwa in harmony.
The u is schwa in medium.
The y is schwa in syringe.