"Signal" is used this way throughout physics. For example, CERN has an explainer on the search for the Higgs boson that says,

> When physicists search for a signal of the Higgs boson, they select particle collisions with observed characteristics similar to those a Higgs production would feature.

The "signal" comes from the process being studied, and the rest (at least whatever parts can be modeled stochastically) is "noise." One person's signal is another person's noise, depending on what each person is studying.

1. https://cms.cern/physics/higgs-boson-terms-and-definitions

Oxford defines “signal” as:

1. a gesture, action, or sound that is used to convey information or instructions, typically by prearrangement between the parties concerned.

2. an electrical impulse or radio wave transmitted or received.

The second definition doesn’t require intent.

If you take signal as simply “discernible from noise”, then it doesn’t require intent or a unique sender.

Just something that I started doing the last couple of years, searching for for ‘etymology of <insert word here>’ instead of definition. It usually leads to pretty interesting and informative results, particularly when a word selection feels strained.

Not necessarily. E.g. analyzing data from natural events is still "signals processing", even though there is no intent behind an earth quake etc.

I doubt it. E.g. the headline "New gravitational wave detector picks up possible signal" (1) does not imply intent, just measuring a definite event and not just noise.

1) https://www.livescience.com/gravitational-wave-detector-stra...