Stretch is a 7 letter word with e as the only vowel. Twelfth is another 7 letter words containing only one vowel.
Rhythm = contains six letters and the only vowel in this word is the "y".
The word strength has only one vowel.The adopted word from German, schnapps, also has only one vowel.
Strengths
strength
thrusts
Many people maintain that "y" is not a vowel and cite "rhythms" as the answer to this question. I do not agree.
Defencelessness
stir
It is "A" Dragon, It is "An" only if the first letter is a vowel in the next word.
The letter i is the only vowel in which. It has a short i sound as in the homophone word witch.
Yes
Thousands of them. harp, myth, cold, etc.
The word baby has the long vowel sound which is the letter a.
Earshot
The word "rhythm" does not have a vowel, or end in the letter y.
Rhythm The 7-letter word is Rhythms