Meaning

noun a detachable lock; has a hinged shackle that can be passed through the staple of a hasp or the links in a chain and then snapped shut

verb fasten with a padlock

originFrom earlier pad lock (19th c.); Middle English padlock, padlokke, from pad-, of unknown origin, + lok (“lock”). Perhaps originally a lock for a pad (“gate”), or a gate opening to a path, or a lock for a basket or pannier, from UK dialect pad (“a pannier”).

Etymology from Wiktionary, CC BY-SA 3.0