The four signs on an ordinary deck are a French design of the later fifteenth century, and they were drawn the way they are for a reason that has nothing to do with meaning.
A printer's solution
Before the French signs, German packs used hearts, bells, acorns and leaves, and Italian and Spanish packs used cups, coins, swords and batons. All of those are pictures, and a picture has to be drawn. The French signs replaced them with four flat silhouettes in two colours, shapes simple enough to be printed with a stencil rather than cut individually.
That is why they are solid blocks rather than outlines, why two are red and two are black, and why they survived to become the international standard deck while the older regional patterns stayed regional. They were cheaper to make.
The name
Coeur is simply the French word for heart, and the sign is one of the four the French pattern took over directly from the German suits rather than inventing. English kept the translation.
The correspondence to the Latin suits
Cartomancers reading a French-suited deck have long mapped the four signs onto the older Latin suits, hearts to cups, tiles to coins, clovers to batons and pikes to swords. That mapping is a convention of reading rather than a historical derivation of one sign from another, and this atlas records it as such.