The idea that salvation is an idea unique to Christianity ought to shock us. After all, don't the vast majority of religions center on salvation? Buddhists long for release from suffering and the illusion of the material world. Muslims seek a heavenly paradise. Hindus desire to escape the cycle of reincarnation. But what is fascinating is that when we use the word "salvation" to describe the hope of these religions, we actually use it in a way that is in utter contrast to our non-religious use of the word.
Given that the etymological root of "salvation" is in the word "save" (both come from the Latin salvare), consider the following secular uses of this word: "A passing motorist dove into the icy water to save the drowning child", "The surgeon saved my father's life by performing open heart surgery" or even "The goalkeeper made six spectacular saves over the course of the game." Two ideas are common to these examples. The first is the idea of rescue and the second is that of inability. When we use the word "save" in a non-religious context, we assume that the object itself is utterly incapable of some action and is rescued from the natural course of events by some external intervention.
In this sense, I would argue that the word salvation is inappropriate to describe how other religions envision our reconciliation with God. If we really take "salvation" to imply "rescue", then it seems to me that this word can only truly be used to describe the Christian gospel. In fact, to avoid any confusion, I will substitute the word "rescue", "rescued" and "rescuer" for the words "salvation", "saved" and "savior" from now on to capture what Christians mean (or ought to mean!) when they use these words
~ Neil Shenvi