Meaning & use
rhombus
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Meanings
nouncountablemathematics
A flat shape with four straight sides of equal length, whose opposite corners match but which usually has no right angles.
Grammar: Plural is rhombuses or rhombi: draw a rhombus, draw two rhombuses.
Patterns
- a rhombus with equal sides
The kite was cut in the shape of a rhombus.
In a rhombus, the diagonals cross at right angles.
Draw a rhombus by tilting a square to one side.
nouncountable
A diamond-shaped figure used in designs, patterns or on signs.
Grammar: Used when the shape appears as a decoration or marking.
The floor tiles form a repeating pattern of rhombuses.
The warning sign has a yellow rhombus on it.
A red rhombus appears at the center of the flag.
Word forms
| plural | rhombuses |
|---|---|
| plural | rhombi |
Common combinations
- area of a rhombus
- Find the area of a rhombus by multiplying its diagonals and halving.
- draw a rhombus
- Use a ruler to draw a rhombus on the page.
- diagonals of a rhombus
- The diagonals of a rhombus cross at the center.
- rhombus shape
- The window has a rhombus shape.
- perimeter of a rhombus
- The perimeter of a rhombus is four times one side.
Synonyms and how they differ
- diamond
- Diamond is the everyday word for the shape, whereas rhombus is the precise geometry term.
- lozenge
- Lozenge is an older word for a diamond shape and is now mostly used in design and heraldry.
- parallelogram
- A parallelogram is a wider group that includes any four-sided shape with matching parallel sides, while a rhombus must have all sides equal.
Word family
- rhombi noun
- one plural form of rhombus
- rhombic adjective
- shaped like a rhombus
- rhomboid noun
- a parallelogram whose sides are not all equal
- rhombohedron noun
- a solid with six rhombus-shaped faces
Commonly confused: rhombus or rhomboid? rhombus or square?
rhombus vs rhomboid
A rhomboid has opposite sides equal but adjacent sides unequal. A rhombus has all four sides equal.
rhombus vs square
A square is a special rhombus that has four right angles. A rhombus does not have to have them.
Practice
Which shape has four equal sides but corners that are usually not right angles?
Choose one answer.
A rhombus has four equal sides and is usually tilted so its angles are not 90 degrees. A rectangle has right angles but only opposite sides equal.
Make it your own
Write a sentence using “rhombus”, then check it and compare it with the examples above.