weekly (used especially of organizations that meet weekly).
he was forced to eke out a meager living scribbling hebdomadal feuilletons
Though I doubt we have sufficient data to produce statistically significant results by this method, other epigraphic evidence also points to the spread of the hebdomadal week in the first century.
The hebdomadal letter does not always represent the same weekday every year.
Incidentally, when looking to see whether I really meant gerund, I encountered ‘ hebdomadal ’ - occurring every seven days.
That hebdomadal structure, dividing into four the 28 days of the lunar calendar and allocating one day to be special, is an ancient thing, probably pre-dating the Hebrews, probably going back to the Sumerians.