dark matter

Từ điển WordNet v3.1 - WordNet Dictionary

noun

(cosmology) a hypothetical form of matter that is believed to make up 90 percent of the universe;
it is invisible (does not absorb or emit light) and does not collide with atomic particles but exerts gravitational force
• Topics:
cosmology, cosmogony, cosmogeny
• Hypernyms:
matter
• Part Meronyms:
weakly interacting massive particle, WIMP