The phrase "to confirm the breakout" means to have enough evidence or proof that a significant change or event is truly happening or going to happen. Full definition
Fresh positions can be initiated at $ 330, which will confirm a breakout above the resistance. (dailybitcoinnews.com)
Again, look for a strong pickup in volume to confirm the breakout action and your breakout buy entry. (morpheustrading.com)
When you get a trend breakout signal, confirm the breakout risk is not more than 1 % of your core account size; if so, go to the next step. (trendfollowingmentor.com)