Definition
A telephone service feature that allows an outside caller to dial a specific extension within an organization directly, without going through a switchboard or operator. In aviation contexts, DID numbers are often published for Flight Service Stations, ATC facilities, and weather briefing services so pilots can reach the correct desk immediately.
Plain English
A phone number that rings straight through to the right person or desk, instead of going through a main switchboard.
Context Anchor
Seen in FAA abbreviation lists and sometimes in facility or airport contact information where a direct phone line is being identified.
Derivation
Direct (straight, without intermediate steps) + inward (coming into the organization from outside) + dial (to place a call). The name simply describes what the service does: an outside call dials directly inward to a specific internal line.
Why Pilots Care
When a pilot needs a weather briefing, to file or amend a flight plan, or to coordinate with a specific facility, a DID number saves time and avoids being routed through a general switchboard during time-sensitive situations.
Intuition Check
DID does not refer to a round cockpit dial or instrument. Here, dial means placing a phone call to a direct phone line.
Example Sentence 1
The chart supplement lists a DID number for the Flight Service Station, so I called the briefer directly.
Example Sentence 2
Airport operations provided a DID line so pilots could contact the duty officer directly during after-hours.