1To cut into (a line), to force oneself into a crowd or conversation; to squeeze in or intrude; to interrupt.
駅の改札で前に割り込まれて腹が立った。
I was annoyed when someone cut in front of me at the station ticket gate.
会話にいきなり割り込むのは失礼だ。
It is rude to suddenly interrupt a conversation.
混んだバスに無理やり割り込んだ。
He forced his way onto the crowded bus.
2To fall below (a certain level) — used for stock prices, sales, or other numerical values dropping under a threshold.
株価がサポートラインを割り込んだ。
The stock price broke below the support line.
今期の売上は目標を割り込んでしまった。
This quarter's sales fell below the target.
気温が平年値を割り込む日が続いている。
Days continue in which temperatures fall below the average for the season.