Pinniped and Walrus

Pinniped noun - Aquatic carnivorous mammal having a streamlined body specialized for swimming with limbs modified as flippers.

Walrus and pinniped are semantically related. In some cases you can replace term "Walrus" with "Pinniped", this nouns are similar.

Walrus noun - Either of two large northern marine mammals having ivory tusks and tough hide over thick blubber.

Pinniped and walrus are semantically related. You can use "Pinniped" instead a noun "Walrus".