Where in the bible does it say Isaac means laughter?

Isaac was the only son of Abraham through Sarah, his wife.

Abraham and Sarah did not have any children. But, when were very old (he was 100 and she was 90), God promised Abraham that Sarah would produce a son for him, Abraham laughed. Later, Sarah laughed to.

The account is chronicled in the The Bible Book of Genesis.

(Genesis 17:17) 17 At this Abraham fell upon his face and began to laugh and to say in his heart: "Will a man a hundred years old have a child born, and will Sarah, yes, will a woman ninety years old give birth?"

(Genesis 18:9-15) 9 They now said to him: "Where is Sarah your wife?" To this he said: "Here in the tent!" 10 So he continued: "I am surely going to return to you next year at this time, and, look! Sarah your wife will have a son." Now Sarah was listening at the tent entrance, and it was behind the man. 11 And Abraham and Sarah were old, being advanced in years. Sarah had stopped having menstruation. 12 Hence Sarah began to laugh inside herself, saying: "After I am worn out, shall I really have pleasure, my lord being old besides?" 13 Then Jehovah said to Abraham: "Why was it that Sarah laughed, saying, 'Shall I really and truly give birth although I have become old?' 14 Is anything too extraordinary for Jehovah? At the appointed time I shall return to you, next year at this time, and Sarah will have a son." 15 But Sarah began to deny it, saying: "I did not laugh!" For she was afraid. At this he said: "No! but you did laugh."

(Genesis 21:1-7) 21 And Jehovah turned his attention to Sarah just as he had said, and Jehovah now did to Sarah just as he had spoken. 2 And Sarah became pregnant and then bore a son to Abraham in his old age at the appointed time of which God had spoken to him. 3 Accordingly Abraham called the name of his son who had been born to him, whom Sarah had borne to him, Isaac. 4 And Abraham proceeded to circumcise Isaac his son when eight days old, just as God had commanded him. 5 And Abraham was a hundred years old when Isaac his son was born to him. 6 Then Sarah said: "God has prepared laughter for me: everybody hearing of it will laugh at me." 7 And she added: "Who would have uttered to Abraham, 'Sarah will certainly suckle children,' whereas I have given birth to a son in his old age?"

See the attached links on Isaac, Abraham & Laughter.