Abbreviations & Definitions
By letter: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | 0-9
X Shex  Sundays and holidays excepted 
X-Whse  Ex-warehouse 
X/C  ssheX / sshinC 
X/X  ssheX / ssheX 
XPS  Extruded Polystyrene. Manufactured from styrene, is a thermal plastic material manufactured by a variety of extrusion processes. Polystyrene foam board and extruded foam sheet have properties that make it a frequent choice for thermal insulation, sheathing, roofing and building and construction application. 
XS  In excess of 
Xylene  Xylene, a colorless liquid, is an aromatic hydrocarbon of which there are several forms. Xylenes are used as solvents, as components of aviation fuel, and as raw materials for the manufacture of dyes, fibers and films. Of the different forms of xylenes, paraxylene is commercially the most important. 
Xylenes  Xylene comes in three different isomers: ortho-xylene, meta-xylene, and para–xylene. The first and last of this threesome have important chemical uses. All of them, separately or together, make superior motor gasoline blendstock. Refinery reformate and steam cracker pyrolysis gasoline, when put through an aromatics recovery unit, yield all three, plus another eight carbon compound called ethylbenzene, in the form of mixed xylenes.