1. in the sense of answer
- clue
- answer
- explanation
- solution
- cue
- pointer
- basis of
- lead
- requisite for
- foundation for
- precondition
- condition
- means
- essential
- route
- way
- passport
- path
- formula
- secret
- gloss
- guide
- interpretation
- glossary
- translation
- explication
- exposition
- clarification
- index
- annotation
- code
- legend
2. in the sense of tone
- pitch
- tone
- tonality
- timbre
- modulation
- tone colour
3. in the sense of style
4. in the sense of crucial
- central
- crucial
- indispensable
- essential
- fundamental
- basic
- critical
- pivotal
- dominant
- decisive
- principal
- vital
- prime
- salient
- major
- chief
- main
- leading
- significant
- important
Example Sentences of Key
1. She lost the key to success.
2. The key unlocks the hidden treasure.
3. His advice was the key factor.
4. Knowledge is the key to understanding.