formant

A band of frequencies, in a sound spectrum, that have a greater intensity; they determine the quality of a sound; especially the characteristic sounds of the consonants.

The resonances of the vocal tract are called formants. Trying to hear the separate formants in a vowel is difficult. We are so used to a vowel being a single meaningful entity that it is difficult to consider it as a sound with separable bits. But it is possible to say vowels so that some of their component parts are more obvious.

Synonym of formative (“language unit, typically a morph, that has a morphological function”).