Films , symbol for adults only (former certification, still used in X-rated , X-rating )
• symbol for beer strength (in XX , XXX , etc.)
• symbol for choice (on a ballot paper)
• Christ (from Greek letter × (chi), representing ch)
• symbol for Cross (as in King's X )
• symbol for error
• experiment(al)
• explosive
• (ital.) Physics , symbol for exposure dose
• extension
• extra
• extraordinary
• Chem. , symbol for a halogen (as in MgX )
• symbol for a kiss
• symbol for the location of a place or point on a map, diagram, etc
• symbol for his (or her) mark
• (ital.) Electricity , symbol for reactance
• Roman numeral for ten
• symbol for any unknown, unspecified, or variable thing, factor, number, or person. See also X-ray
• Biochem. , symbol for xanthosine
• X-ray
• symbol for xylonite (a plastic)
• Genetics , indicating a sex chromosome in humans and most animals (as in X chromosome , X-linked , XYY syndrome )