Cross
Cross turns up in 2 fields: vacuum, surveying. Here is what it means to the people in each one.
Cross in vacuum
Fitting with several ports meeting at a central body, used to hang gauges, pumps and valves off one point.
A tube fitting in which four or more branches meet at a common centre: a 4-way cross, a 5-way or a 6-way cube. Crosses let one chamber port carry a gauge, a pump and a vent valve, and they are a standard building block of lab plumbing alongside tees, elbows and nipples. Every branch adds surface area and costs conductance, so a cross between a pump and a chamber trades speed for convenience.
"Put a 6-way cross on top of the turbo, gauge on one arm, leak valve on another, RGA on the third."
Cross in surveying
A simple optical or mechanical tool used to establish perpendicular lines from a main survey baseline.
This traditional instrument features sighting slits or prisms set exactly at right angles to each other. A surveyor places it on the main traverse line and looks through the sights to guide a rodman into a position exactly ninety degrees to the side. It was heavily used for taking lateral offset measurements to irregular boundaries like rivers or fences.
"Grab the optical cross from the truck so we can lay out these building grid offsets."