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ABCD is a list of the first four letters in the English alphabet. It may also refer to:



  • ABCD matrix analysis, a type of ray tracing technique used in the design of some optical systems
  • ABCD-parameters, a type of properties describing the electrical behavior of linear electrical networks
  • ABCD Schema, a highly structured data exchange and access model for taxon occurrence data (specimens, observations, etc. of living organisms), i.e. primary biodiversity data


Other uses[edit]