A stopping or interruption of something that had been continuous; e.g., contact, supply, or a flow being cut off.
彼との連絡が途絶えた。
Contact with him was cut off.
その地域への物資の供給が途絶え、支援が急務となった。
Supplies to the area were interrupted, and aid became urgent.
会話の途絶えがあって、しばらく気まずかった。
There was a pause in the conversation, and it was awkward for a while.