The word “echo” has different meanings depending upon the context. Its simplest
definition is “a sound that is repeating after the original sound ended”
(www.yourdictionary.com), yet the meaning that seems most popular makes reference to
the repetition of a sound, typically heard in big, empty spaces (mountains, caves). In
living creatures, such as bats, the term “echo” (or echolocator) refers to self-generated
sounds that permit them to orient through labyrinthic environments in complete darkness
(Wenstrup & Portfors, 2011). The noun “echolocator” is also used to designate some blind
persons who make clicking noises with their mouths and use the reflected echoes to
estimate the size and distance of perceived objects and surfaces (Milne, Anello, Gooddale,
& Thaler, 2015). Also in humans, the definition of echo is “one who closely imitates or
repeats another's words, ideas, or acts” (Merriam-Webster's Dictionary of English Usage,
1994).