The word(s) "sister" appears 21 time(s) in 12 verse(s) in Quran in Saheeh International translation.

(1) Allah instructs you concerning your children: for the male, what is equal to the share of two females. But if there are [only] daughters, two or more, for them is two thirds of one's estate. And if there is only one, for her is half. And for one's parents, to each one of them is a sixth of his estate if he left children. But if he had no children and the parents [alone] inherit from him, then for his mother is one third. And if he had brothers [or sisters], for his mother is a sixth, after any bequest he [may have] made or debt. Your parents or your children - you know not which of them are nearest to you in benefit. [These shares are] an obligation [imposed] by Allah. Indeed, Allah is ever Knowing and Wise.

(2) And for you is half of what your wives leave if they have no child. But if they have a child, for you is one fourth of what they leave, after any bequest they [may have] made or debt. And for the wives is one fourth if you leave no child. But if you leave a child, then for them is an eighth of what you leave, after any bequest you [may have] made or debt. And if a man or woman leaves neither ascendants nor descendants but has a brother or a sister, then for each one of them is a sixth. But if they are more than two, they share a third, after any bequest which was made or debt, as long as there is no detriment [caused]. [This is] an ordinance from Allah, and Allah is Knowing and Forbearing.

(3) Prohibited to you [for marriage] are your mothers, your daughters, your sisters, your father's sisters, your mother's sisters, your brother's daughters, your sister's daughters, your [milk] mothers who nursed you, your sisters through nursing, your wives' mothers, and your step-daughters under your guardianship [born] of your wives unto whom you have gone in. But if you have not gone in unto them, there is no sin upon you. And [also prohibited are] the wives of your sons who are from your [own] loins, and that you take [in marriage] two sisters simultaneously, except for what has already occurred. Indeed, Allah is ever Forgiving and Merciful.

(4) They request from you a [legal] ruling. Say, "Allah gives you a ruling concerning one having neither descendants nor ascendants [as heirs]." If a man dies, leaving no child but [only] a sister, she will have half of what he left. And he inherits from her if she [dies and] has no child. But if there are two sisters [or more], they will have two-thirds of what he left. If there are both brothers and sisters, the male will have the share of two females. Allah makes clear to you [His law], lest you go astray. And Allah is Knowing of all things.

(5) [Allah] will say, "Enter among nations which had passed on before you of jinn and mankind into the Fire." Every time a nation enters, it will curse its sister until, when they have all overtaken one another therein, the last of them will say about the first of them "Our Lord, these had misled us, so give them a double punishment of the Fire. He will say, "For each is double, but you do not know."

(6) O sister of Aaron, your father was not a man of evil, nor was your mother unchaste."

(7) [And We favored you] when your sister went and said, 'Shall I direct you to someone who will be responsible for him?' So We restored you to your mother that she might be content and not grieve. And you killed someone, but We saved you from retaliation and tried you with a [severe] trial. And you remained [some] years among the people of Madyan. Then you came [here] at the decreed time, O Moses.

(8) And tell the believing women to reduce [some] of their vision and guard their private parts and not expose their adornment except that which [necessarily] appears thereof and to wrap [a portion of] their headcovers over their chests and not expose their adornment except to their husbands, their fathers, their husbands' fathers, their sons, their husbands' sons, their brothers, their brothers' sons, their sisters' sons, their women, that which their right hands possess, or those male attendants having no physical desire, or children who are not yet aware of the private aspects of women. And let them not stamp their feet to make known what they conceal of their adornment. And turn to Allah in repentance, all of you, O believers, that you might succeed.

(9) There is not upon the blind [any] constraint nor upon the lame constraint nor upon the ill constraint nor upon yourselves when you eat from your [own] houses or the houses of your fathers or the houses of your mothers or the houses of your brothers or the houses of your sisters or the houses of your father's brothers or the houses of your father's sisters or the houses of your mother's brothers or the houses of your mother's sisters or [from houses] whose keys you possess or [from the house] of your friend. There is no blame upon you whether you eat together or separately. But when you enter houses, give greetings of peace upon each other - a greeting from Allah, blessed and good. Thus does Allah make clear to you the verses [of ordinance] that you may understand.

(10) And she said to his sister, "Follow him"; so she watched him from a distance while they perceived not.