echo

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Repetition of a sound by reflection of sound waves from a surface.
• noun The sound produced in this manner.
• noun A repetition or an imitation.
• noun A remnant or vestige.
• noun One who imitates another, as in opinions, speech, or dress.
• noun A sympathetic response.
• noun A consequence or repercussion.
• noun Repetition of certain sounds or syllables in poetry, as in echo verse.
• noun Music Soft repetition of a note or phrase.
• noun Electronics A reflected wave received by a radio or radar.
• noun An echocardiogram.
• intransitive verb To repeat (a sound) by the reflection of sound waves from a surface.
• intransitive verb To repeat or imitate.
• intransitive verb To be repeated by or as if by an echo.
• intransitive verb To resound with or as if with an echo; reverberate.

from The Century Dictionary.

• noun In whist, a response to a partner's signal for trumps.
• noun In bridge, a method of showing the leader how many cards his partner holds in the suit led, or of indicating that the third hand can trump the third round. The first is called the plain-suit echo, the second the down-and-out echo.
• In bridge, to show the leader how many cards the third hand holds in the suit led.
• noun A sound repeated by reflection or reverberation from some obstructing surface; sound heard again at its source; repercussion of sound: as, an echo from a distant hill.
• noun [capitalized] In classical mythology, an oread or mountain nymph, who, according to a usual form of the myth, pined away for love of the beautiful youth Narcissus till nothing remained of her but her voice.
• noun Figuratively, a repetition of the sentiments of others; reproduction of the ideas or opinions of others, either in speech or in writing.
• noun In music, the very soft repetition of a short phrase, particularly in orchestral or organ music.
• noun In architecture, a wall or vault, etc., having the property of reflecting sounds or of producing an echo.
• noun [capitalized] [NL.] In zoology, a genus of neuropterous insects.
• To emit an echo; reflect or repeat sound; give forth an answering sound by or as if by echo.
• To be reflected or repeated by or as if by echo; return or be conveyed to the ear in repetition; pass along by reverberation.
• To produce a reverberating sound; give out a loud sound.
• To emit an echo of; reflect the sound of, either directly or obliquely; cause to be heard by reverberation: as the whispering gallery of St. Paul's in London echoes very faint sounds.
• To repeat as if by way of echo; emit a reproduction of, as sounds, words, or sentiments; imitate the sound or significance of.
• To imitate as an echo; repeat or reproduce the sounds, utterances, or sentiments of: as, the mocking-bird echoes nearly all other creatures; to echo a popular author.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To give an echo; to resound; to be sounded back.
• transitive verb To send back (a sound); to repeat in sound; to reverberate.
• transitive verb To repeat with assent; to respond; to adopt.
• noun A sound reflected from an opposing surface and repeated to the ear of a listener; repercussion of sound; repetition of a sound.
• noun Fig.: Sympathetic recognition; response; answer.
• noun (Myth. & Poetic) A wood or mountain nymph, regarded as repeating, and causing the reverberation of them.
• noun (Gr. Myth.) A nymph, the daughter of Air and Earth, who, for love of Narcissus, pined away until nothing was left of her but her voice.
• noun 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 signaled for trumps.
• noun A signal showing the number held of a plain suit when a high card in that suit is led by one's partner.
• noun (Mus.) a set organ pipes inclosed in a box so as to produce a soft, distant effect; -- generally superseded by the swell.
• noun (Mus.) a stop upon a harpsichord contrived for producing the soft effect of distant sound.
• noun to give loud and continuous applause.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A reflected sound that is heard again by its initial observer.
• noun computing : The displaying on the command line of the command that has just been executed.
• noun The letter E in the ICAO spelling alphabet.
• verb of a sound or sound waves, intransitive To reflect off of a surface and return to someone who has heard it already.
• verb by extension, transitive To repeat back precisely what another has just said: to copy in the imitation of a natural echo.