No one knows everything about his or her own culture. In all societies, there are bodies of specialized cultural knowledge that are gender specific–they are known to men but not women or vice versa. In many societies there are also bodies of knowledge that are limited largely to particular social classes, occupations, religious groups, or other special purpose associations.
Gender based skills, knowledge, and perceptions largely stem from the fact that boys and girls to some extent are treated differently from each other in all societies. While there may be considerable overlap in what they are taught, there are some things that are gender specific. In the Western World, for instance, it is more common to teach boys about the skills of combat and how machines work. Girls are more often exposed to the subtleties of social interaction and the use of clothing and makeup to communicate intentions. Not surprisingly, men are more likely to know how to fix their car or computer, while women generally are better at predicting the outcome of social interaction and make finer distinctions in fabric and color terms.
There are many professions in large-scale societies. Each one usually has its own terminology and specialized tools. Lawyers, medical doctors, soldiers, and other specialists use numerous technical terms in their professions. To make it even more obscure for outsiders, these professionals often use abbreviations to refer to their technical terms. For instance, orthopedic surgeons commonly refer to a particular kind of knee operation as ACL surgery. ACL stands for anterior cruciate ligament. Most people outside of the medical fields who have not had this surgery are unlikely to know where this ligament is and what it does, let alone know what the abbreviation means.