Most places where the bible use the word head, it speaks of that thing above the neck. A few places, it does not. Head carries the figurative meaning of authority figure in English, but what figurative meanings did it have in koine Greek? (The New Testament language) Here, Katherine Clark Kroeger gives her view of how head was understood by the ancients, and uses a lot of old sources to support it:
…In the case of “head,” we have strong indications of the definition as it was understood by the ancients. Homer called the innermost part of a stream its “head,” while Eusthatius explained that the river’s head is that which generates the whole river.9 Herodotus tells of a river that rose from thirty-eight separate sources or “heads.”10 Philoponus, in the sixth century a.d., noted that a river, when it rushed upon a rock, might divide and become two streams, even though it had but a single source (kephalē),11 and the medical writer Galen observed that a river arising from a single spring might be larger at the “head” (kephalē) than farther down along its banks.12 The Digest of Justinian declared authoritatively, “The head is the place whence the water issues forth.”13
Not only with respect to flowing water was the head considered the place of beginning. Aristotle himself declared that the head was the source or beginning of life, with human sperm being created in the head, traveling down the spinal cord, flowing into the genitals, and so procreating the human race.14 Thus, the ancient writers sometimes referred to sexual intercourse as “diminishing one’s head.”15 Artemidorus of Ephesus maintained that the head was like one’s father because, just as the head was the source of light and life for the whole body, so a father was the source of life for his son.16 “The head is like one’s parents because it is the source or cause of one’s having life.”17 Shortly after the New Testament period, Plutarch told of those who thought the brain “to be the source of generation.”18 Philo, a Jewish contemporary of Jesus and Paul, wrote, “As though he were the head of a living being, Esau is the progenitor of all those members who have been mentioned.”19
Among other values, the head as the source of paternity was understood by the early Christian fathers. Irenaeus equates “head” with “source” when he writes of the “head and source of his own being.”20 Hippolytus emphasized the productivity of this bodily member when he designated the head as the characteristic substance from which all people were made.21 He noted, “In the head is said to be the brain, formulating the being from which all fatherhood is produced.”22 Cosmas Indicopleustes (sixth century a.d.) called Adam the “head” of all people in this world because he was their source and father.23
Photius, a ninth century Byzantine scholar, was renowned for his vast knowledge of classical authors and his preservation of numerous quotations from works that are now lost to us. He drew upon earlier scholars passionately committed to preserving classical Greek and promoting a continued knowledge of its words and forms. These works Photius edited and incorporated into a formidable lexicon intended as a reference book to aid later writers in understanding the vocabulary of classical and sacred authors. He quite specifically stated that “head” was considered to be a synonym for procreator or progenitor.24 …
An Orphic fragment probably from the sixth century b.c., declares: Zeus was born first, Zeus last, god of the bright bolt: Zeus is the head [kephalē], Zeus the middle, from Zeus are all things made.25 Sometimes, however, the last line runs, “Zeus the beginning [archē], Zeus the middle, and Zeus the end.” Four times Zeus is called head, kephalē,26 and three times archē, source or beginning.27 Thus, the two terms appear synonymous in this context, as has been noted by various classical scholars.28 …
Other artistic representations sometimes depict the head as productive of growing life. The myth of Athena springing from the head of Zeus is known in story form, mosaics, frescoes, and vase paintings. Ancient Orphic burials sometimes contained figurines of the soul reemerging into the world after remaining nine years beneath the bosom of Persephone, queen of the dead. From the head of the goddess sprout up new little heads, some surrounded by leaf buds as they grow to full reincarnation status. The theme of head as starting point for growth is unmistakable.
Thus, St. Augustine declared love to be the head that produced all the other Christian virtues. From its fertile soil sprang the rest of the spiritual graces. ..
Exactly this concept of growth is what we find explicated by the Apostle Paul in Colossians 2:19 and Ephesians 4:15–16, his two sole passages dealing with the function of the head in relation to the body. In both of these passages, he maintains that the head not only causes growth but also causes the body to build itself up. A more expanded paraphrase might read as follows: ) Paul gives very nearly the same concept when he turns to the relationship of head and body in Ephesians chapter 4, certainly a passage to take very seriously when we are considering Ephesians chapter 5. The Apostle wrote: Let us grow up in all things unto Him who is Christ, the Head. He causes the body to build itself up in love as the head provides empowerment according to the proportion appropriate for each member as they are bound and supported by every sinew. (Eph. 4:15–16, the author’s translation)
Frequently, we assume that the Bible uses “head” to imply “boss” or “chief,” and so we miss the assurance of this passage. Here the focus is on the function of the head in producing growth. Every part of the body is connected to the head, and, if the connecting nerve is severed, even a perfectly healthy member will wither. But every part is also interconnected to every other part, and each has a different function that causes it to depend on every other member. …
Medical writers considered the head as the crucial element in treating the entire body. Aetius Amidenus Medicus insisted that a physician must always begin with the head, because it was the root and source of the entire bodily condition.30 If the head was indisposed, then the whole body was affected.31 Aretaeus wrote, “From the head is the source of life, because the head is the place of perception and the starting point of the nerves.”32 Philo announced that the limbs of the body draw life from the forces in the head.33 The commonly held anatomical view of antiquity, that the head was the source of the body’s existence, led the foremost exegete of the early church to further metaphorical uses.
From the head, John Chrysostom said, the senses “have their source and fount” 34: In the head are the eyes both of the body, and of the soul. . . . All the senses have thence their origin and source. Thence are sent forth the organs of speech, the power of seeing and of smelling, and all touch. For thence is derived the root of the nerves and bones.35
Athanasius stated, “For the head (which is the source) of all things is the Son, but God is the head (which is the source) of Christ.”38
Cyril, Archbishop of Alexandria, wrote of Adam: Therefore of our race he became first head, which is source, and was of the earth and earthy. Since Christ was named the second Adam, He has been placed as head, which is source, of those who through Him have been formed anew unto Him unto immortality through sanctification in the Spirit….
BTW, I completely believe Grudem when he claims the primary meaning of head is not source. I also believe egalitarians when they say the primary meaning is not leader. The most common meaning seem to be the body part above the neck. “But their understanding is not the primary meaning of head” is a red herring argument. Kroeger was discussing what she probably believes to be the second meaning.