The story
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A hammer that consists of a large, heavy, broad and flat block of metal (the head) attached to a handle typically 0.5 meter to 1 meter long. The sledgehammer's design is meant to allow it to be swung powerfully, and to distribute force over a wide area upon impact. Full definition →
Etymology from Wiktionary, CC BY-SA 4.0.