The word(s) "thread" appears 6 time(s) in 5 verse(s) in Quran in Saheeh International translation.

(1) It has been made permissible for you the night preceding fasting to go to your wives [for sexual relations]. They are clothing for you and you are clothing for them. Allah knows that you used to deceive yourselves, so He accepted your repentance and forgave you. So now, have relations with them and seek that which Allah has decreed for you. And eat and drink until the white thread of dawn becomes distinct to you from the black thread [of night]. Then complete the fast until the sunset. And do not have relations with them as long as you are staying for worship in the mosques. These are the limits [set by] Allah, so do not approach them. Thus does Allah make clear His ordinances to the people that they may become righteous.

(2) Have you not seen those who claim themselves to be pure? Rather, Allah purifies whom He wills, and injustice is not done to them, [even] as much as a thread [inside a date seed].

(3) Have you not seen those who were told, "Restrain your hands [from fighting] and establish prayer and give zakah"? But then when fighting was ordained for them, at once a party of them feared men as they fear Allah or with [even] greater fear. They said, "Our Lord, why have You decreed upon us fighting? If only You had postponed [it for] us for a short time." Say, The enjoyment of this world is little, and the Hereafter is better for he who fears Allah. And injustice will not be done to you, [even] as much as a thread [inside a date seed]."

(4) And do not be like she who untwisted her spun thread after it was strong [by] taking your oaths as [means of] deceit between you because one community is more plentiful [in number or wealth] than another community. Allah only tries you thereby. And He will surely make clear to you on the Day of Resurrection that over which you used to differ.

(5) [Mention, O Muhammad], the Day We will call forth every people with their record [of deeds]. Then whoever is given his record in his right hand - those will read their records, and injustice will not be done to them, [even] as much as a thread [inside the date seed].