Trapezium, plural trapezia, may refer to:

• Trapezium, in British and other forms of English, a trapezoid, a quadrilateral that has exactly one pair of parallel sides
• Trapezium, in North American English, an irregular quadrilateral with no sides parallel
• Trapezium (bone), a bone in the hand
• Trapezium Cluster, a group of stars in the Orion Nebula
• Trapezia (genus), guard crabs
• Trapezium (novel), a Japanese novel by Kazumi Takayama

• Trapezius, a muscle