Definitions:
a thing that is said, written, or done as a reaction to a question, statement, or situation

a solution to a problem or dilemma

a person or thing regarded as the equivalent to a better-known one from another place

say or write something as a reaction to someone or something

act in reaction to (a sound such as a phone ringing or a knock or ring on a door)

defend oneself against (a charge, accusation, or criticism)

be suitable for fulfilling (a need); satisfy