I guess these words are interchangeable in most cases .... A "Reply" is usually a reaction to something in speech or writing, though it can also be a reaction of a different kind, like a gesture or an action. In general, it seems to me that a "reply" is a more cognitive thing that you'll normally receive from a person. ex- "reply" to a letter; He didn't reply to her greeting. "Answer" means to speak or write in reply. It implies the satisfying of a question, demand, call, or need . ex- I asked him a simple question and he gave me a long and confusing answer. "answer a phone call" - I don't think we "reply" to a phone call.

REPLY means 1) When you reply to something that someone has said or written to you, you say or write an answer to them: e.g. He was gone before we could reply to his last remark. SYNONYM: answer 2) write back in answer to someone: e.g. She replied with a long letter the next day. 3) respond by a similar action or gesture: e.g. During a number of violent incidents farmers threw eggs and empty bottles at police, who replied with tear gas. ANSWER means 1) say or write something as a reaction to someone or something: e.g. ‘Of course I can,’ she answered. 2) provide the required response to (a question in a test or quiz): e.g. Answer the questions below for a chance to win a holiday. 3) act in reaction to (a sound such as a telephone ringing or a knock or ring on a door): e.g. Digby answered the door.

Reply and answer respond to a question. A response is generally a reaction to something A reply is usually a reaction or an answer to something in speech or writing An answer seems to be, above all, some sort of a solution to a question or a problem.

What do you mean?