Os and Sesamoid

Os noun - A hard brittle blue-grey or blue-black metallic element that is one of the platinum metals; the heaviest metal known.

Sesamoid and os are semantically related. In some cases you can replace term "Sesamoid" with "Os", this nouns are similar.

Sesamoid noun - Any of several small round bones formed in a tendon where it passes over a joint.

Os and sesamoid are semantically related. You can use "Os" instead a noun "Sesamoid".