envelope
An envelope usually contains only one letter.
This is a common brain teaser. The answer is envelope.
The word itself has eight letters and a physical envelope can contain a single written letter.
spoonsful
That's puzzling.
voldemort
The word possibly is an 8-letter word that contains the letter B.
Clippers (LA)
Envelope.
FEEDBACK
Double-u
boldface, feedback
envelope
therein
strength