- A reflected sound that is heard again by its initial observer.
- The letter E in the ICAO spelling alphabet.
- (computing) The displaying on the command line of the command that has just been executed.
- (whist, bridge) A signal showing the number held of a plain suit when a high card in that suit is led by one's partner.
- (figuratively) Sympathetic recognition; response; answer.
- (whist, bridge) 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.
- (of a sound or sound waves, intransitive) To reflect off of a surface and return.
- (by extension, transitive) To repeat (another's speech, opinion, etc.).
"Sid echoed his father's point of view."
- (by extension, transitive) To repeat back precisely what another has just said: to copy in the imitation of a natural echo.