A postulate is a statement that is taken as truth, a number of postulates form a theorem which are the basis of mathematics as we know them today, postulates are sentences that are true and make sense, for example, a postulate is:
"If you have a segment "AB" and you draw a point "C" in the segment AB you´ll have that the sum of AC and BC would be equal to the segment AB"
That´s a postulate that is true and is part of a bigger theorem.
