from
The Collaborative International Dictionary of English v.0.48
Four-way \Four"-way`\, a.
Allowing passage in either of four directions; as, a four-way
cock, or valve. --Francis.
[1913 Webster]
{Four-way cock}, a cock connected with four pipes or ports,
and having two or more passages in the plug, by which the
adjacent pipes or ports may be made to communicate;
formerly used as a valve in the steam engine, and now for
various other purposes. In the illustration, a leads to
the upper end of a steam engine cylinder, and b to the
lower end; c is the steam pipe, and d the exhaust pipe.
[1913 Webster]