Sentence:  Initially, the English, Welsh, Scots and Irish unions refused to send national <WSD>sides</WSD>, preferring instead to send touring <WSD>sides</WSD> like the Barbarians, the Penguins, the Co-Optimists, the Wolfhounds, Crawshays Welsh, and the Public School Wanderers. 
Meaning of the word marked with <WSD> tags:  A sports team.