Social construct.

[Objectivist]

I've seen some examples of what a social construct is using Google.

It seems fairly simple but I've come to  a conclusion I can't think of much that isn't a social construct.

For example with a tree, I don't think there's an exact precise definition of when a dead tree stops being a tree or when a tree becomes a tree and stops being a seed.

Pretty much all definitions are based on one person communicating to another person vaguely what something is.  Even if it's a precise explanation by normal social standards.

Am I missing the point of what a social construct is or has anyone got an obvious example of a non social construct.

I don't think that a tree is a social construct.  Nor is a mountain, a cloud, or anything else that exists in reality apart from human choice.  I think that culture is a social construct in that it is a product of a group or society of people.  

I don't agree with you that definitions are based on "one person communicating to another person vaguely what something is".  I think proper definitions serve a very important function and they are objective, i.e., based on facts and there are rules to defining concepts that derive from the process of concept formation.  A definition names the things a concept subsumes in terms of their essential characteristics.  Essential characteristics are what makes a thing what it is and also distinguish the thing from other things. For instance, man is the rational animal. This definition names the fundamental characteristic that makes man what he is and distinguishes him from other animals.  They need to be precise in order to serve their function, which is to facilitate cognition.  In fact, when someone is using vague definitions, they are probably trying to pull the wool over your eyes.  

Definitions are the carriers of truth.