Trapezium

Origin

Recorded since 1570, from Late Latin trapezium, from Ancient Greek τραπέζιον ("irregular quadrilateral", literally a little table), diminutive of τράπεζα ("table")", itself from τρά- ("four") + πέζα ("foot, edge").

Full definition of trapezium

Noun

1. (geometry, British) A four-sided polygon with two sides parallel; a trapezoid (modern sense)
2. (geometry, US) A four-sided polygon with no parallel sides and no sides equal; a simple convex irregular quadrilateral.
3. A bone of the carpus at the base of the first metacarpal, or thumb.
4. A region on the ventral side of the brain, either just back of the pons Varolii, or, as in man, covered by the posterior extension of its transverse fibers.

Usage notes

(geometry, US, four-sided polygon with no sides parallel and no equal sides) The terms trapezium and trapezoid have partially swapped meanings in the US and Canada as compared with the rest of the world.

Synonyms

• (geometry, British, four-sided polygon with two parallel sides) US trapezoid
• (geometry, US, four-sided polygon with no sides parallel and no equal sides) British irregular quadrilateral.

Related terms

• trapeze
• trapeziform
• trapezius
• trapezoid