Hi Sally,

A nonmathematical term might be "squashed box". You could take a square cardboard box with the bottom and top removed and push it down to skew it into a rhombus.

Stephen La Rocque.>

Hi Sally,

As a math consultant in elementary schools I spent a lot of time in classrooms with students. Most schools have pattern blocks where 2 of the figures are rhombuses. Some students - all the way up to high school - will still insist on calling them diamonds, but many students, even in K will gladly learn the new word, especially if they are told it's a new word that most people don't know - the same with trapezoid. In K, they may not remember the word but will recognize it
when they hear it again. The important thing is for them to be introduced to the new word so that it's not a big surprise a few years later when it's harder to change from diamond to rhombus.

Good luck!
Diane