A sus4
The A sus4 chord consists of the A (Perfect unison), D (Perfect fourth) and E (Perfect fifth) notes.

How to play the A sus4 chord
- Find A (Root) on the piano keyboard
- Add D (Perfect fourth) — 5 semitones above A
- Add E (Perfect fifth) — 7 semitones above A
- Press all 3 notes simultaneously to sound the A sus4 chord