(chemistry) Initialism of epichlorohydrin.

(military, US) Initialism of Enhanced Combat Helmet.

The use of echoes to detect objects as observed in bats and other natural creatures. Also known as biosonar.

A reflected sound that is heard again by its initial observer. / An utterance repeating what has just been said.

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

A poem constructed by the surrealist technique of alternately writing a stanza and then "mirroring" it in some fashion to create the following stanza.

Any of the species of small spined monotremes in family Tachyglossidae, the four extant species of which are found in Australia and southern New Guinea.

(Greek mythology) A female monster who, along with Typhon, mothered the vast majority of the famous monsters and creatures of Greek mythology.

(Greek mythology) An oread, punished by Hera by losing her own voice and only being able to mimic that of others. / (astronomy) 60 Echo, a main belt asteroid.

A level or rank in an organization, profession, or society. / (cycling) A line of riders seeking maximum drafting in a crosswind, resulting in a diagonal line across the road.