密

Computing

security (e.g. data, password, etc.)

Mathematics

probability density

trade secret

privacy of communications

In ref. to 密閉, 密集, 密接

three Cs; three conditions that facilitate the transmission of infectious diseases (closed spaces, crowds, and close contact)

phalanx

close coverage reportage; close reporting

overcrowded city

leaking of a secret; leakage of a secret

precision tool

secret vote; secret ballot

Physics

magnetic flux density

extremely complete (thorough, careful) and detailed

Mathematics

probability density function

going into a huddle (over); holding secret (closed-door) conference (about); laying heads together in secret consultation

ultra-precision machining; ultra-precision cutting

secret ballot

non-disclosure agreement; NDA

detailed and careful; scrupulous; meticulous; elaborate

military secret

Cabinet Secretariat classified fund; secret Cabinet expenses

recording audio without consent; secret recording

privacy of correspondence

precision engineering