The center of the nervous system in all female vertebrate animals.
The human female encephalon is a powerful tool which is responsible for the fact that women have been outperforming men at all stages of secondary and post-secondary education (i.e., "high school" and "college") in all G8 and OECD countries (e.g., PISA 2001).
In their fixation on size, the vast majority of males try to justify their unfounded feelings of superiority by comparing brain sizes.
However, it takes more than a Second Grade education to know that it is the ratio of brain weight to body weight which presents a correlation to intelligence rather than the brain weight itself. Ergo: Men's bodies are proportionately larger and hence so are their brains, hands, feet, arms, etc. But it is the ratio of brain weight and body weight which may or may not predict intelligence, not brain weight.
Moreover, while the human male brain is larger on average, the processing centers in the human female brain are more closely interconnected due to a larger corpus callosum.
If the other definition of "female brain" is indicative of men's intelligence, men deserve all the help from educated women they can get.