I. noun — [ mass noun] 1.
[Ecology] the chemical inhibition of one plant (or other organism) by another, due to the release into the environment of substances acting as germination or growth inhibitors.
II. derivatives allelopathic /əˌliːlə(ʊ)ˈpaθɪk / adjective
– origin 1950s: from Greek allēl- ‘one another’ + -pathy.