Is There Such A Word As 'Dipthong'..in Regards To English? If So..proper Spelling/meaning

The word you're looking for is 'diphthong'.
It means a sound that's made in pronouncing a single syllable that actually changes from one vowel to another. It's a difficult concept to explain, but try saying the words 'coin', 'loud' and 'side' very slowly and concentrate on the change in vowel sound in the middle of them and you should grasp the idea!! Good luck!

Another way of defining diphthong is "two vowel sounds pronounced as one syllable; it begins with one vowel sound and gradually changes to another vowel."  Ex. The oi sound in toy or boil.
Derived from Greek.  Di-double
                                 phthong-sound,voice