Is this correct? “Calculates a color between two colors at a specific increment.”

I find this usage of the word “increment” a bit odd.

Not sure what the context is. I would agree with your assessment of the word “increment” though.

My experience is that functions with docs like you’re describing are usually something like:

(define (gradient from to [pct 0.5]) ...)

So the argument would be a percent or fraction, where 0 = from and 1 = to.

The exception to that would be if trying to find a palette color opposite the two inputs (ie on a color wheel, a color that would make a triangle opposite the center between the inputs), but that wouldn’t need an increment or fraction either.

It’s taken from the docs of Processing: https://processing.org/reference/lerpColor_.html

Your interpretation is spot on. I just wondered whether “increment” could be used in other ways than “something to be added”.

Not with respect to any linear interpolation that I’m aware of ;)

Perhaps they mean it as a synonym to “step”, where 1.0 would be the full step to the next color (second input)?

Could be. I’ll file a bug report and see what they say.

I have noticed that they use “friendly” language in some places in order to make the documentation easier to read - but it tends to confuse me.

I am spoiled by the Racket docs.