As an interjection sssh
is alternative form of shh.
As a noun ssh is
a program and protocol for securely logging in to and running programs on remote machines across a network, with encryption to protect the transferred information and authentication to ensure that the remote machine is the one desired.
As a verb ssh is
to use ssh to connect to a remote computer.
As an initialism SSH is
secure Shell a networking protocol by which two computers are connected via a secure channel.
ssh
Noun
(head)
A program and protocol for securely logging in to and running programs on remote machines across a network, with encryption to protect the transferred information and authentication to ensure that the remote machine is the one desired.
Verb
(head)
To use ssh to connect to a remote computer.