There are multiple definitions:

1. difference-in-differences(English)

   • model using panel ordinary least squares regressions
   • DM, OLS, WISDOM
   • Model(ing), Statistics
   • https://doi.org….1111/dme.14928

2. Densely Inhabited District(English)

   • ACE, ADI, COVID-19, JACSIS
   • Public Health
   • https://doi.org…889-023-16557-z

3. double immunodiffusion(English)

   • BAL, ELISA, FLD, IgG, MF
   • Immunology, Respiratory system
   • http://pubmed.n…ih.gov/2410168/

4. delayed ischemic deficit(English)

   • refers to ischemic sequelae following spontaneous subarachnoid hemorrhage
   • HHS, SAH, VSP
   • Neuropathy, Surgery, Cerebrovascular event
   • https://doi.org…uro.2004.01.006