A large structural timber—a main beam used in roofing or construction—which Jesus employs in one of his most vivid and memorable illustrations. In the Sermon on the Mount (Matt 7:3-5) and its Lukan parallel (Luke 6:41-42), he contrasts the dokos ('beam' or 'log') in one's own eye with the karphos ('speck' or 'splinter') in a neighbor's eye. The hyperbolic image is deliberately absurd: how can you offer to extract a tiny splinter from someone else's eye when an entire roof beam protrudes from your own? The metaphor teaches self-examination before criticism. Spanish 'viga' and French 'poutre' both denote a heavy structural beam, preserving the humorous disproportion that makes the saying so effective.