# Definition of parallelogram in US English:

## parallelogram

### noun

• A four-sided plane rectilinear figure with opposite sides parallel.

• ‘His vertical stripes have been put onto a slant, and whittled down to slender triangles or widened into parallelograms or pyramids.’
• ‘Four congruent sides lie on two parallel lines, and pairs of these sides define parallelograms of equal area.’
• ‘The building is in the form of a rectangular parallelogram, 294 feet five inches long by 219 feet nine inches wide, covering an area of 7,188 square yards.’
• ‘Because the direction of the slope did not coincide with the axis of the view, the architect made the plan in the shape of a parallelogram.’
• ‘In the deformation, the parallelograms always remain parallelograms, because their opposite sides remain equal, but the angles change.’

### Phrases

• parallelogram of forces

• A parallelogram illustrating the theorem that if two forces acting at a point are represented in magnitude and direction by two sides of a parallelogram meeting at that point, their resultant is represented by the diagonal drawn from that point.

• ‘Parallelogram of Forces is the famous theorem that can be used to determine the resultant of two forces acting at a point.’
• ‘This caused a deflection, which if it be analyzed, both directions taken together would be found to be a parallelogram of forces.’

### Origin

Late 16th century: from French parallélogramme, via late Latin from Greek parallēlogrammon, from parallēlos ‘alongside another’ + grammē ‘line’.

## parallelogram

/ˌperəˈleləˌɡram//ˌpɛrəˈlɛləˌɡræm/