Definition of dipthong:
(n) :
Misspelling of diphthong. [(phonetics) A complex vowel sound that begins with the sound of one vowel and ends with the sound of another vowel, in the same syllable.]
(n) :
Obsolete spelling of diphthong. [(phonetics) A complex vowel sound that begins with the sound of one vowel and ends with the sound of another vowel, in the same syllable.]