Only in sports is the word used commonly that way. The normal word is "rescue". However, there is nothing that prevents you from extending sports metaphors to other areas of life, if you want. For example, you could say "He really hit a home run!", which is a baseball expression, to say that your friend did something exceptional. Or, you could say "You can't say that. It's out of bounds", which is a sports term, to indicate that your friend said something inappropriate. You can do the same with "save", so long as you keep in mind that you are extending a sports metaphor: "The man prevented the boy from unknowingly stepping out in front of a truck. It was a close save."

I think you've got the idea of using SAVE as a noun, as in, "good save", when someone keeps the ball from going out of bounds, or when a person averts a problem. However, if you just put the word SAVE on a tool, it would be confusing. The most likely interpretation would be that people would think they need to save (i.e. not throw away) the tool itself.

While "save" is commonly used as a verb to express actions like rescuing or preserving, it is less common to use "save" as a noun in the context of rescue. As you mentioned, it is more frequently used as a noun in sports (referring to preventing a goal, for example) or in computing. However, language is flexible, and in specific contexts or for creative purposes, you might find instances where "save" is used as a noun to refer to an act of rescue. Keep in mind that it might not be universally understood this way, and using more conventional terms like "rescue" or "safety" would generally be clearer to your audience. If you want to indicate that a tool is used for rescue, it might be better to use more explicit terms like "rescue tool" or "emergency tool" to ensure clarity and convey the intended meaning to users. Using symbols or graphics that universally represent rescue or safety could also be effective in conveying the tool's purpose.

A tool with just the word "save": Nope that doesn't exist. But, look at this link. https://search.brave.com/images?q=life%20preserver%20saver It has photos of "life saver"s. This is two words though. And always two words: "life", and "saver". It is the only thing I can think of as a "save" tool. Hope that helps.

There are various nouns using ‘save’, but they don’t have the meaning you are looking for. ‘Saver’ = someone who saves, usually money. I’m a compulsive saver. ‘Life saver’ is the name of a candy. It is also something used to save someone’s life, but it is usually used figuratively: ‘Chat GPT was a life saver. There was no way I could have finished the project without it.’ My brother was a life saver. I couldn’t have moved without his help and his truck.’ It can be used to mean ‘life preserver’ but sounds inaccurate in my opinion. What you are talking about is called ‘rescue equipment’.