Questions about example sentences with, and the definition and usage of "Breached"

A: Yes, these are common words.
Breached means to break through something.
Threshold is the point marking the entry to a room or a house. Here, it is used as a metaphor for the point or limit it is necessary to reach before something happens.
"His behavior has finally reached the threshold of being illegal."
"The reaction will not occur until the saturation threshold is reached."