Strong’s Greek
G4914 — sunetheia
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
συνήθεια
sunetheia — pronounced soon-ay'-thi-ah
from a compound of 4862 and 2239; mutual habituation, i.e. usage:--custom. see GREEK for 4862 see GREEK for 2239
2 occurrences in the KJV.
John 18:39
But ye have a custom, that I should release unto you one at the passover: will ye therefore that I release unto you the King of the Jews?
1 Corinthians 11:16
But if any man seem to be contentious, we have no such custom, neither the churches of God.