Echo n. : A sound reflected from an opposing surface and repeated to the ear of a listener; repercussion of sound; repetition of a sound.

Echo n. : Fig.: Sympathetic recognition; response; answer.

Echo n. : A wood or mountain nymph, regarded as repeating, and causing the reverberation of them.

Echo n. : A nymph, the daughter of Air and Earth, who, for love of Narcissus, pined away until nothing was left of her but her voice.

Echo v. t. : To send back (a sound); to repeat in sound; to reverberate.

Echo v. t. : To repeat with assent; to respond; to adopt.

Echo v. i. : To give an echo; to resound; to be sounded back; as, the hall echoed with acclamations.

Example:
How to prove or disprove findings on Echo ranging formula?

Taxonomy
chain saws, Blowers, outdoor power equipment, Trimmers, Power, Hedge Trimmers, lawn equipment, USA, Brushcutters, Shred, Edgers, Gas Powered, professional-grade, equipment, Power Blowers, hand-held, ECHO chain saws, products.

Defination from the web:
Maker and distributor of landscape equipment such as grass trimmers, leaf blowers, hedge clippers, and chain saws.