Beluga and Porpoise

Beluga noun - Valuable source of caviar and isinglass; found in Black and Caspian seas.

Porpoise and beluga are semantically related in cetacean mammal topic. In some cases you can use "Porpoise" instead a noun "Beluga", when it comes to topics like aquatic mammal.

Porpoise noun - Any of several small gregarious cetacean mammals having a blunt snout and many teeth.

Beluga and porpoise are semantically related in cetacean mammal topic. You can use "Beluga" instead a noun "Porpoise", if it concerns topics such as aquatic mammal.