Japanese leek and Onion plant

Japanese leek noun - Asiatic onion with slender bulbs; used as early green onions.

Onion plant and Japanese leek are semantically related. In some cases you can use "Onion plant" instead a noun phrase "Japanese leek".

Onion plant noun - Bulbous plant having hollow leaves cultivated worldwide for its rounded edible bulb.

Japanese leek and onion plant are semantically related. Sometimes you can replace phrase "Japanese leek" with "Onion plant", this phrases are similar.