Here's a description from Texplainer:
A point of order is a parliamentary action that points out a violation of the House rules. It is the House speaker's responsibility to ensure that the rules are enforced, but the point of order allows legislators to interject and declare a violation that has been overlooked.
Once declared, a point of order takes precedent on the floor, and the speaker must decide whether there has been a violation before continuing. If the speaker overrules a point of order, business continues as usual.
. . . A point of order can potentially stall the process for longer. Debate on a point of order can potentially continue indefinitely, preventing any debate on the merits of the legislation. And points of order can apply to any parliamentary rule, which creates a vast number of potential opportunities to stall legislation.
On very rare occasions, a point of order can kill a bill — for example, if it calls attention to the lack of an enacting clause. The Texas Constitution requires all legislation to begin with the words "be it enacted." If a representative notices these words are missing and alerts the speaker with a point of order, the bill will die. Usually these types of errors are caught before it hits the floor.
And more from Wikipedia.
