D defs.my
Entry 1 sense Webster, 1913

dee

/(dē)/ · IPA /diː/
01 n. an electrode with a large interior cavity, shaped like the letter "D", used in opposed pairs to accelerate particles in a cyclotron.
  1. 1.
    an electrode with a large interior cavity, shaped like the letter "D", used in opposed pairs to accelerate particles in a cyclotron.(Physics)