Definition of "RD"

RD

noun
countable and uncountable, plural RDs
1. (astronomy) Initialism of red dwarf.
2. (US) Initialism of restricted data.
  Quotations
  Under these restrictions, the only way for nuclear information that had been classified as RD to be controlled under UCNI is for the information to be declassified and then for circumstances to change such that the information becomes sufficiently sensitive to warrant reassertion of some degree of control.
  1995, National Research Council, Division on Earth and Life Studies, Commission on Geosciences, Environment and Resources, A Review of the Department of Energy Classification
3. (US, uncountable) Initialism of rural delivery, formerly used when addressing mail.
4. (professional title) registered dietitian
5. (sports) Abbreviation of right defence/defense.: The right wing player defensive position
6. (US, law enforcement) Initialism of reporting district..