The Meanings and Variations of “Sister”
Sister, from the Old English word sweoster and cognate with the Latin term soror, means not only “a female with one or more parents in common” but has also come, by extension, to refer to a woman with whom one has a bond or a common interest.
It also applies to national or racial commonality, as in the term “soul sister,” which in American English describes a black female. In addition, it can refer loosely to a female relative or a girl or woman with whom one has an affinity, including among feminists; it is also slang for referring to a female in general. In religious contexts, it denotes a female member of a religious order. Because nuns often served as nurses, in British English, sister is still synonymous with nurse.
Sis is an informal abbreviation, often used in direct address by a sibling, as is sissy, though this term acquired the pejorative connotation of an effeminate man. The quality of being a sister, literally or figuratively, is sisterhood; the term also applies to a society of sisters, such as a religious community of women.
Sister-german is a technical legal term pertaining to the default definition of sister—“a woman or girl who has both of the same parents as a given person,” as opposed to a half sister, who shares only one parent, or a stepsister, the daughter of a stepparent. (The term german, from the Latin word germanus, means “having the same parents” and is unrelated to the proper noun referring to a person from Germany.)
A blood sister is literally a sister by birth or figuratively someone with whom one shares a bond of loyalty; this term, inspired by “blood brother,” alludes to the ceremonial exchange of blood between two men, often by mingling blood at the point of a slight self-inflicted wound. “Big sister” refers to one’s older female sibling or to a woman who mentors a girl to whom she is not related.
Phrases that include the word include “sister act,” a term from vaudeville describing a variety act consisting of two or more sisters, and “sob sister,” slang for an advice columnist or a writer of sentimental stories supposed to appeal primarily to women, alluding to the emotional reaction expected of female readers when reading such material. “Weak sister” is an allusion to the supposed inferiority of women that refers to an ineffectual, unreliable, or weak person in a group.
Meanwhile, a sister language is one in the same language family, such as Spanish as compared to Portuguese and vice versa, while a sister city is a municipality that has established a cultural-exchange connection with a city in another country. In construction, to sister is to strengthen a structural element by attaching a similar component to it.