When you break something, you ruin it. When you take a break, you stop and rest. If you play catch during your lunch break, try not to break any windows.
The verb break means to fracture or crack or destroy something while the noun refers to an interruption or a little time off. To "break the ice" is to warm up a conversation that's a little awkward or cold because the people involved don't know one another. In theater, the superstitious saying "break a leg" is a way of wishing "good luck" without jinxing someone — strange, but true.