A formant is a frequency peak in the radiated spectrum of a sound. Note: Some earlier writers defined the term formant as ‘a resonance of the vocal tract.’ It is important to differentiate characteristics of the resonator’s sound transfer potential from characteristics of the radiated sound at the mouth opening, which is a result of the interaction of both the voice source and the resonator. Sound transfer potential and the radiated sound may diverge significantly in higher sung sounds where harmonics are widely spaced.
Formant detuning is the tuning of a resonance frequency peak away from a harmonic to weaken its formant effect. Used with F2 in cis female and/or treble upper range to reduce shrillness and with F1 in cis male voices to avoid fR1 :1fo tracking on close vowels; what some pedagogues call ‘whoop’ or ‘hoot’ timbre.
Formant tuning refers to reshaping the vocal tract by means of articulation to adjust its resonances to obtain better matches between tube resonances and available source harmonics.
Formant tracking is the tuning of a resonance to follow or track a specific harmonic, such as fR1 :1fo tracking of what some pedagogues call ‘whoop’ or ‘hoot’ timbre (upper treble voice strategy) or fR1 :2fo tracking of the yell or of belting.
These definitions are taken from the Terminology and Definitions for Science-Informed Voice Pedagogy resource on the NATS Science-Informed Voice Pedagogy website.