Geometry

[nightowl]

What name is a parallelogram having adjacent sides of unequal length?

[JohnPPotts]

A parallellogram. If its sides were all the same length it would be a rhombus (a sort of squashed square, or diamond shape) and if it had one set of parallell sides of unequal lengths (the others necessarily not being parallell) it would be a trapezium

[woofgang]

so what's a paralopiped?

[Hippy]

A small dog with two legs of unequal length and long floppy ears. Similar to a quadrolophidactyl except that it doesn't climb trees or eat seaweed.

[Phantaxus]

Parallelepiped - a solid body of which each face is a parallelogram.(OED)

[Phantaxus]

its a Rhomboid

[firefly]

In the same way a square can be a rectangle but a rectangle cannot be a square.

[del_1690]

A rectangle can be a square, when all its sides are of equal length and all corners are at 90 degrees.