Spit vs Saliva

What is the difference between spit and saliva? Nothing is different except for how we think about each of them. This is called the social construction of reality. The reality is how we experience the world and the social construction is how our society influences how we think about certain things. Today in my sociology class, our teacher asked a student to spit in a spoon and everyone immediately started saying "ew that's gross". Then after the student filled the spoon up with spit, our teacher asked him if he wanted to put the spit back in his mouth and everyone continued to scream "ewww". But then my teacher brought up a good point, he started to tell us facts about how saliva is very important to the human body and then asked us... Why does saliva turn into spit as soon as it leaves your mouth and automatically turn gross when you start calling it spit? Even though they are exactly the same... But that is because our society has always taught us that spit is gross even from an early age, even though everyone is constantly swallowing their own spit. So what is "more gross," Spit or Saliva?