笑点的英文是"punchline"。它的来源是来自英文"punch"，意思是重击，引申为笑话的结局或笑点。

例句：

"The punchline of the joke is 'Why was six afraid of seven? Because seven eight nine.'"

笑话的笑点是：“为什么六号害怕七号？因为七八九。”

"The punchline of the joke is 'Why couldn't the bicycle stand up by itself? Because it was two-tired.'"

笑话的笑点是：“为什么自行车站不起来？因为它两缺一轮。”

"The punchline of the joke is 'Why did the tomato turn red? Because it saw the salad dressing.'"

笑话的笑点是：“为什么西红柿变红了？因为它看见沙拉酱了。”