Nightshade and Poison-berry

Nightshade noun - Any of numerous shrubs or herbs or vines of the genus Solanum; most are poisonous though many bear edible fruit.

Poison-berry and nightshade are semantically related. In some cases you can replace phrase "Poison-berry" with "Nightshade", this terms are similar.

Poison-berry noun - Eurasian herb naturalized in America having white flowers and poisonous hairy foliage and bearing black berries that are sometimes poisonous but sometimes edible.

Nightshade and poison-berry are semantically related. You can use "Nightshade" instead a noun phrase "Poison-berry".