Definition of "dense"

dense

/dɛns/

adjective
comparative denser, superlative densest
1. Having relatively high density.
2. Compact; crowded together.
3. Thick; difficult to penetrate.
  Quotations
  And Vickers launched forth into a tirade very different from his platform utterances. He spoke with extreme contempt of the dense stupidity exhibited on all occasions by the working classes. He said that if you wanted to do anything for them, you must rule them, not pamper them.
  1918, W[illiam] B[abington] Maxwell, chapter XIII, in The Mirror and the Lamp, Indianapolis, Ind.: The Bobbs-Merrill Company
4. Opaque; allowing little light to pass through.
5. Obscure, or difficult to understand.
6. (mathematics, topology) Being a subset of a topological space that approximates the space well. See the Wikipedia article on dense sets for a mathematical definition.
7. Slow to comprehend; of low intelligence. (of a person)
  Quotations
  There are times when systems like GPT-4 seem to mimic human reasoning, but there are also times when they seem terribly dense. “These behaviors are not always consistent,” Ece Kamar, a Microsoft researcher, said.
  2023 May 16, Cade Metz, “Microsoft Says New A.I. Shows Signs of Human Reasoning”, in The New York Times‎
noun
plural denses
1. A thicket.