# prn (10-prn.us)

People say "PRN" to mean "as needed" or "when necessary." It comes from the Latin "pro re nata" and shows up on prescription bottles, work schedules, and care plans. A nurse might work PRN shifts, or a patient might take a pain pill PRN for breakthrough pain.

## What a model may hear
- printer device (Windows and DOS systems): treat it as a reserved filename for the default printer, which can cause errors if used as a folder or file name
- pull request number (GitHub and code review): look for a numbered pull request or expect discussion of code changes
- pseudo-random noise (cryptography and signal processing): assume discussion of sequences used for testing or masking signals
- perceived relevance network (information retrieval research): expect technical discussion of ranking or neural retrieval models

## Where people and models part ways
- Says: "I need this PRN"
  Means: I need it occasionally, not on a fixed schedule
  May be taken as: the model may assume printer output or generate code using PRN as a filename
  Say instead: "I need this as needed, not on a regular schedule"
- Says: "Check the PRN schedule"
  Means: Look at the as-needed staffing shifts
  May be taken as: the model may search for a GitHub pull request or printer queue
  Say instead: "Check the as-needed staffing schedule"
- Says: "PRN medication list"
  Means: List of medicines taken only when symptoms occur
  May be taken as: the model may filter for technical papers or generate printer configuration
  Say instead: "List of as-needed medications for symptom relief"
- Says: "Add a PRN order"
  Means: Add a medical order for medication to be given as necessary
  May be taken as: the model may create a file named PRN or reference a code change
  Say instead: "Add a medical order for as-needed medication"

## Tips
- Say "as needed" or "pro re nata" once if the medical meaning matters to you
- Avoid using PRN alone as a filename or variable name in any system
- In healthcare contexts, spell out "as needed" first, then use PRN in parentheses
- If you mean printer, say "printer" or "print to file" explicitly
- In coding contexts, use longer variable names like "pullRequestNum" instead

## Often confused with
- PRN: same letters, but uppercase may signal medical; lowercase or mixed case often signals tech
- PRN file: a file extension for printer files, not medical orders
- PRN code: medical shorthand versus pseudo-random noise in cryptography
- NPR: reversed letters, a media organization, not as-needed
- PRN nursing: specifies the medical context clearly
- pro re nata: the full Latin phrase, unambiguous but less spoken