Achillea and Milfoil

Achillea noun - Any of several plants of the genus Achillea native to Europe and having small white flowers in flat-topped flower heads.

Milfoil and achillea are semantically related. In some cases you can replace term "Milfoil" with "Achillea", this nouns are similar.

Milfoil noun - Ubiquitous strong-scented mat-forming Eurasian herb of wasteland, hedgerow or pasture having narrow serrate leaves and small usually white florets; widely naturalized in North America.

Achillea and milfoil are semantically related. You can use "Achillea" instead a noun "Milfoil".