I would propose the word trigonal pyramidal or pyramidal . This is because the bond angle in ammonia ( also known as NH3) is about 107 degrees. Also please note that the number of bonding pairs of electrons in ammonia (NH3) is 3 and the Number of lone pairs of electrons in ammonia(NH3) is 1. Finally it has 8 valence electrons (5 + 3x1 = 8).