The Greek noun dokos refers to a large wooden beam or log — the kind used in construction to support a roof or structure. Jesus uses it in one of His most memorable and convicting illustrations about judgment and hypocrisy.
The parable of the speck and the log (Matthew 7:3–5; Luke 6:41–42) uses dokos for devastating rhetorical effect. How can you see the speck in your brother's eye while a whole beam is in your own? The absurdity of the image drives the point home: self-righteous judgment of others is inversely proportional to self-awareness. The dokos represents the blindness that comes with spiritual pride. Jesus is not forbidding discernment — He says 'first take the log out of your own eye, then you will see clearly to remove the speck from your brother's eye.' Genuine correction comes from humility, not superiority.