Meaning "distance" and "sound," a telephone is the end user terminal in a telephone or voice over IP (VoIP) network. Telephone typically refers to a desktop or wall-mounted unit, whereas portable phones are called just plain "phones" or "cordless phones," "cellphones" and "smartphones," the latter two also known as "mobile phones."
In 1876, Alexander Graham Bell's words, "Mr. Watson. Come here! I want you!" ushered in the age of telephony. See telephony
A Century Ago
At the turn of the 20th century, people were "communicating over the wire" with instruments such as this Blake wall phone. (Image courtesy of Nortel Networks.)