وَعَدَ — يَعِدُ — عِدْ
Translation: He promised; he promises; promise!
ItemFormExplanation
Rootو ع دInitial wāw is radical
PastوَعَدَWāw visible
PresentيَعِدُWāw deleted under a specific condition
CommandعِدْBuilt from the relevant jussive stem
Verbal nounعِدَةٌAlso reflects a specific weak-root outcome
Contrast this with مِوْزَانٌ → مِيزَانٌ: wāw becomes yāʾ after kasrah. That is substitution, not deletion. First identify the exact operation and the vowel environment.