pseudo-tty definitionBerkeley Unix
networking device which appears to an application program
as an ordinary terminal but which is in fact connected via the network to a process running on a different host
or a windowing system. Pseudo-ttys have a slave half and a control half. The slave tty (/dev/ttyp*) is the device that user programs use and the control tty (/dev/ptyp*) is used by daemons
to talk to the net.