Butter bean and Shell bean

Butter bean noun - Bush bean plant cultivated especially in southern United States having small flat edible seeds.

Shell bean and butter bean are semantically related. In some cases you can use "Shell bean" instead a noun phrase "Butter bean".

Shell bean noun - A bean plant grown primarily for its edible seed rather than its pod.

Butter bean and shell bean are semantically related. Sometimes you can replace phrase "Butter bean" with "Shell bean", this phrases are similar.