gang: [12] Gang originally meant ‘going, journey’. It was borrowed from Old Norse gangr, which goes back ultimately to the same Germanic source (the verb *ganggan ‘go’) as produced the German past participle gegangen ‘gone’ and Old English gangan ‘go’ – still preserved in Scottish gang ‘go’ and in gangway [17]. Originally literally a ‘way for going’.
The word’s modern meaning seems to have developed via ‘quantity carried on a journey’ (a common usage in Scottish English well into the 19th century) and ‘set of articles carried together’ to (in the 17th century) ‘group of workmen’ and ‘group of people acting together for a (bad) purpose’. [gang etymology, gang origin, 英语词源]