(medicine) Resistant to multiple drugs (especially to multiple antibiotics).

(topology, of a subset of a topological space) Given a subset S of a topological space X, a point x whose every neighborhood contains at least one point distinct from x that belongs to S.

Fertilization by the union of gametes of different plants (sometimes of different species). / (by extension) The mutual exchange of ideas or concepts from different fields for mutual benefit.

Synonym of spaceplane