# signal (0-signal.org)

A signal is a sign or message that carries meaning. People say they will "signal" something when they want to hint, warn, or communicate without stating it directly. It can also mean a sound, gesture, or light that tells someone to act, like a traffic signal or a phone signal.

## What a model may hear
- Unix signal (operating systems and process management): Send an interrupt or termination command to a running process, such as SIGKILL or SIGTERM
- digital signal processing (audio, image, and communications engineering): Treat the input as a waveform or time-series data to filter, transform, or analyze
- cryptographic protocol (the Signal messaging app and its libraries): Apply end-to-end encryption, forward secrecy, or the Signal Protocol specifically
- machine learning feature (data science and predictive modeling): Interpret as meaningful predictive information versus noise in a dataset
- electrical or radio signal (hardware and networking): Assume discussion of voltage levels, antennas, bandwidth, or physical layer transmission

## Where people and models part ways
- Says: "Send me a signal when you're done"
  Means: Let me know or message me when finished
  May be taken as: The model may discuss inter-process communication mechanisms or SIGUSR1
  Say instead: "Message me when you're done"
- Says: "There's no signal here"
  Means: My phone has no bars or connection
  May be taken as: The model may analyze signal-to-noise ratios or debug antenna hardware
  Say instead: "My phone has no cellular reception here"
- Says: "Signal that you understand"
  Means: Show or indicate that you understand
  May be taken as: The model may describe sending a Unix signal or setting a flag bit
  Say instead: "Say or show that you understand"
- Says: "The signal is weak"
  Means: The indication or evidence is not strong
  May be taken as: The model may calculate dBm values or diagnose RF propagation issues
  Say instead: "The evidence for that is weak"

## Tips
- Say 'message me' instead of 'signal me' to avoid encryption or OS meanings
- Add 'on my phone' or 'cellular' if you mean phone reception
- Use 'indicate' or 'show' rather than 'signal' when you mean give a sign
- In technical contexts, specify 'Unix signal' or 'Signal Protocol' to get the right domain
- If you mean the messaging app, capitalize it as 'Signal' to reduce ambiguity

## Often confused with
- sign: More general; lacks technical OS or encryption meanings
- cue: Theatrical or behavioral prompt; no computing sense
- prompt: Direct instruction; in AI it means the input text, not an interrupt
- interrupt: Always technical in computing; more explicit than signal
- message: Avoids Unix and DSP meanings; clearer for communication
- noise: Often paired with signal technically; opposite in common speech