Duck-billed platypus and Egg-laying mammal

Duck-billed platypus noun - Small densely furred aquatic monotreme of Australia and Tasmania having a broad bill and tail and webbed feet; only species in the family Ornithorhynchidae.

Egg-laying mammal and duck-billed platypus are semantically related. In some cases you can use "Egg-laying mammal" instead a noun phrase "Duck-billed platypus".

Egg-laying mammal noun - The most primitive mammals comprising the only extant members of the subclass Prototheria.

Duck-billed platypus and egg-laying mammal are semantically related. Sometimes you can replace phrase "Duck-billed platypus" with "Egg-laying mammal", this phrases are similar.