echo

noun
A reflected sound that is heard again by its initial observer.
An utterance repeating what has just been said.
A device in verse in which a line ends with a word which recalls the sound of the last word of the preceding line.
Sympathetic recognition; response; answer.
The displaying on the command line of the command that has just been executed.
The letter E in the ICAO spelling alphabet.
(whist) A signal, played in the same manner as a trump signal, made by a player who holds four or more trumps (or, as played by some, exactly three trumps) and whose partner has led trumps or signalled for trumps.
(whist) A signal showing the number held of a plain suit when a high card in that suit is led by one's partner.

verb
(of a sound or sound waves) To reflect off a surface and return.
To reflect back (a sound).
(by extension) To repeat (another's speech, opinion etc.).

Sid echoed his father's point of view.
To repeat its input as input to some other device or system.
(whist) To give the echo signal, informing one's partner about cards one holds.