While actually looking for something else,
I found some helpful information concerning
KEFALH in Peter Cotterell and Max
Turner's Linguistics and Biblical Interpretation(London: SPCK, 1989). See pp. 141-145.
Turner and Cotterell review GNT examples such as Col
2:19; 1 Cor 11:3 and Eph 5:23. They write:
"Now contextually it is by no means certain that Col
2:19 presents Christ as the origin, rather than as the
Lord of the Church, but clearly it would considerably
weaken the thesis if the sense 'source' was part of
the lexical meaning of the Greek word KEFALH ('head');
that is, if it were one of its established senses"
But is "source" one of the established senses of
KEFALH? After discussing LXX and Classical examples
where KEFALH is employed by ancient writers, these
"In other words, as far as we can tell, 'source' or
'origin' was NOT a conventional sense of the word
KEFALH in Paul's time. This does not preclude the
possibility that Paul himself began to use the word in
such a way, but we would need very strong evidence to
support such a view, and in our judgment nothing like
such strength of evidence is forthcoming" (145).
While, as Cotterell and Turner show, there does not
appear to be enough evidence in favor of
"source" being one of the lexical senses of KEFALH in
Paul's time, we do have attestation for the meaning
"ruler" or "authority over." Paul apparently used
KEFALH in this way, when he penned these inspired
words to the Ephesians:
KAI PANTA hUPETAXEN hUPO TOUS PODAS AUTOU KAI AUTON
EDWKEN KEFALHN hUPER PANTA THi EKKLHSIAi (Eph 1:22).