Monophthong
/ˈmɑːnəfθɔːŋ,ˈmɑːnəθɔːŋ/
Definition 1 of 1
Pro Tip 1/3Speech Clarity
Monophthongs are clearer than diphthongs, which can help with pronunciation. 
The monophthong in 'moon' is easier to pronounce than the diphthong in 'town'.
Pro Tip 2/3Length Awareness
Remember that monophthongs can vary in length; some are short, some are long. 
In 'ship', the monophthong is short, but in 'sheep', it's long.
Pro Tip 3/3Accent Variation
The quality of monophthongs can change depending on accents, affecting pronunciation. 
The monophthong in 'park' sounds different in different English accents.