Fourfold: applied to a system of telegraphy in which four messages may be transmitted simultaneously over one wire.

noun. An instrument by means of which four messages may be transmitted simultaneously over one wire.

noun. Sometimes abbreviated quad.

To make quadruplex; arrange for fourfold transmission.

adjective. Fourfold; folded or doubled twice.

adjective. a system by which four messages, two in each direction, may be sent simultaneously over the wire.

adjective. Having four components.

adjective. of or relating to a system in telegraphy by which four messages can be sent on one wire simultaneously.

noun. A quadruplex system

adjective. having four units or components

"The quadruplex was the tempting goal toward which Edison now constantly turned, and after more than a year's strenuous work he filed a number of applications for patents in the late summer of 1874."

multiple  

Heb.  apparuit  bifold  contulit  decimam  

fourfold