ice是冰，break the ice字面意思破冰，引申为打破僵局；打破隔阂；使气氛轻松。

【例句】
The major purpose of his trip was to break the ice, and his itinerary so far has been packed full.
他此行的主要目的是打破僵局，目前的行程已经排满。

I never know how to break the ice and start conversations.
我不知道如何打破沉默开始谈话。