The full form of the root has two instances of the characteristic-vowel, one in its normal position between the first and second consonant and an extra vowel after the second consonant (SD/422). For a biconsonantal-root such as ✶Ad. √ZIR, the full form is ✶ziri. For a triconsonantal-root such as ✶Ad. √KALAB, the full form is ✶kalab.

The full form can be considered the simplest form of words derived from the root. Other patterns of word derivation can move, alter or suppress the vowels of the full form.