Sister

A sister is defined as a female sibling. This means she is a woman or a girl who shares a parent or a parent with another person. A full sister is considered a first-degree relative.

While the term usually describes a family relationship, people often use it endearingly for non-familial bonds. This colloquial usage has caused some confusion in writing. Because of this, some publishers prefer the specific term "female sibling" to avoid any equivocation.

The word "sister" has deep linguistic roots. It comes from the Old Norse language. That language derived the word from Proto-Germanic *swestēr. Both of these ancient linguistic sources carry the same meaning as the modern word. Understanding these roots helps us see how long this concept has existed in human language. The term has remained a stable way to describe this specific kinship for many centuries.

Research shows that sororal relationships, or relationships between sisters, influence how siblings behave. Older sisters often play more with their younger siblings. They are also likely to provide a varied gender role to those younger siblings.

Younger siblings may display more needy behavior when they are near an older sister. Interestingly, younger siblings are often more tolerant of an older sister's bad behavior. Furthermore, a younger sister is less likely to be scolded by older siblings than a younger brother is.

Growing up with sisters can impact the development of brothers. Boys with only one older sister often display stereotypically male behavior. As they gain more sisters, this masculine behavior can actually increase. Conversely, young boys with several sisters may tend to be more feminine. However, most of these boys outgrow these traits by the time they approach pubescence.

Additionally, boys with older sisters are less likely to experience delinquency or certain emotional and behavioral disorders.

Societal and cultural views also shape the sisterly experience. In some cultures, sisters are afforded a role of being under the protection of male siblings. This is especially true for older brothers protecting sisters from bullies or sexual advances.

Studies have also looked at the connection between having an older sister and having constructive discussions about safe sexual practices. Some researchers even study how siblings feel jealousy. Certain studies suggest sisters may show more traits of jealousy toward siblings than brothers do.

There are even specific observations regarding biological and social connections. A study in Perth, Australia, looked at girls who had only younger brothers. It found a "chastity effect" where these girls lost their virginity on average more than a year later than average. Scientists hypothesized this might be due to household errands or pheromones in their brothers' sweat. In a different context, some men without sisters may be less effectual at courtship or romantic relationships.

Sisters have also been a frequent subject in the history of art. Artists have used the bond between sisters to capture human connection. For example, Sofonisba Anguissola painted her sisters playing chess in 1555.

Other artists have depicted sisters in quiet, domestic scenes. These artworks serve as historical records of how these relationships were viewed across different eras and locations.