The best example of a domain-specific language (DSL) among the options given would be "shape."
Domain-specific languages are designed to be highly effective in a specific domain, often providing a higher level of abstraction and specificity than general-purpose programming languages. "Shape" suggests a focus on geometry or graphical representation, which aligns with the concept of a DSL tailored for that particular field.
The other options ("numerous," "close," and "equilateral") could represent various concepts but do not clearly indicate a specific domain or focus like "shape" does.