Definition of "to join issue" [to join issue]

• To take opposing sides in a matter in controversy. (noun)
• (verb-transitive)

Gnu Collaboartive International Dictionary of English: licensed under The Code Project Open License (CPOL)

• "So she left them, and going wherever there were learned persons, she learnt their methods of knowledge till, when she found none equal to debate with her, she made a heap of sand at the gate of some village or town, and in it set up the branch of a rose-apple, and told children to watch near it, saying: 'Whoever is able to join issue with me in debate, let him trample on this bough.'"