If I took a traditional diamond shape and elongated just the bottom sides.
I feel like most would call it a diamond still. Specific term would be a kite. Many wouldn't come up with that, though. It's not an elongated parallelogram. It is not a rhombus.
"Diamonds" on bicycle playing cards have curved edges. They are not a rhombus because sides are not parallel. Most agree that it's the classic diamond shape, though.
People would definitely want to elongate the top and bottom sides because they do not want to draw a sideways square, which is a rhombus, parallelogram, diamond too.
There's no way a human is going to draw 4 equal lines
No one at the end is going to be like "yeah but you have to be sure all sides are equal" when they have some kind of weird kite shape.
There's people out there that wouldn't count a sideways square as a diamond
For me the shape I was thinking of was if you take a simplified 2D version of this 💎, with there being 4 sides, 2 pairs of equal sides but not 4 equal sides
I imagine what people are talking about here is this ♦️ sort of diamond.
I blame me not being a native speaker for thinking of diamon diamond