A boy or man who shares one or both parents with another male offspring; a male sibling. The female counterpart is sister. The term brother, in the plural form brethren or brothers, may also refer to a group of men regarded as a close association or community. A man is often called a brother if he belongs to the same kinship group, religion, country, race, profession, or political party as you, or if he shares your ideas and values.
A brother is often a positive influence on a young child’s upbringing and education in ethics and good actions. Aristotle in his book Nicomachean Ethics says that when an older brother displays positive characteristics, the younger brother imitates these characteristics and emulates him. These habits then become a part of the young man’s character that is hard to break. This is known as the bond of brotherhood. It is this bond that makes people akin and loyal to each other.