Lateral reading is a verification technique where, instead of scrutinising a claim purely within the page or post it appears on, a reader opens new tabs to check what other independent sources say about the same claim or the outlet publishing it in the first place before drawing any conclusion.
The method was named by researchers studying how professional fact checkers actually work, who found that experts spend less time analysing a single page in isolation and more time quickly cross referencing it against other sources before forming any confident judgement about its accuracy or reliability, at least in most well functioning systems.
Compared with simply reading more carefully within one article, lateral reading tends to be faster and more reliable, because it draws on the collective scrutiny of many other sources rather than resting entirely on one reader's own instincts and prior assumptions about a topic they encounter, even if that is not always obvious.