|This essay contains the advice or opinions of one or more Wikipedia contributors. Essays are not Wikipedia policies or guidelines. Some essays represent widespread norms; others only represent minority viewpoints.|
Hearsay is information gathered by one person from another person concerning some event, condition, or thing of which the first person had no direct experience. When submitted as evidence, such statements are called hearsay evidence. As a legal term, "hearsay" can also have the narrower meaning of the use of such information as evidence to prove the truth of what is asserted. Such use of "hearsay evidence" in court is generally not allowed. This prohibition is called the hearsay rule.
Just because an article has a citation from a source, that doesn't make it reliable. If it is an oped page or a newspaper column, that makes it opinion and not fact. This is inherently unreliable.
Hearsay is often claimed when an articles content is disputed due to WP:VERIFY issues, or when proper sources are not cited. Wikipedia relies on its practice of providing verifiable sources as much as possible, to keep the content neutral and accurate.