The McDonald's Golden Arches symbol forms the letter M.
The mark is based on the paired arches used in McDonald's restaurant architecture. When the two curved shapes were joined visually, they created a large, rounded capital M associated with the company's name. The design was introduced as a corporate logo in 1962.
The arches originally had a practical architectural role. They helped make restaurants visible from roads and gave the early buildings a distinctive look. McDonald's later transformed that building feature into a standalone symbol used on signs, packaging, uniforms, advertisements, and merchandise.
The Golden Arches are therefore both an architectural reference and a letterform. They are not simply two unrelated yellow curves. Their connection to the letter M is why the symbol can communicate McDonald's identity even without the company name written beside it.