Definition of hebdomadal in English:
 hebdomadal
adjective hɛbˈdɒməd(ə)lhɛbˈdɑmədl
formal Weekly (used especially of organizations which meet weekly)
 Oxford University's Hebdomadal Council
 Example sentencesExamples
-  Incidentally, when looking to see whether I really meant gerund, I encountered ‘hebdomadal’ - occurring every seven days.
 -  The hebdomadal letter does not always represent the same weekday every year.
 -  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.
 -  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.
 
Origin
  
Early 17th century (in the sense 'lasting seven days'): from late Latin hebdomadalis, from Greek hebdomas, hebdomad- 'the number seven, seven days', from hepta 'seven'.
   Definition of hebdomadal in US English:
 hebdomadal
adjectivehɛbˈdɑmədlhebˈdämədl
formal Weekly (used especially of organizations which meet weekly)
 he was forced to eke out a meager living scribbling hebdomadal feuilletons
 Example sentencesExamples
-  The hebdomadal letter does not always represent the same weekday every year.
 -  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.
 -  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.
 -  Incidentally, when looking to see whether I really meant gerund, I encountered ‘hebdomadal’ - occurring every seven days.
 
Origin
  
Early 17th century (in the sense ‘lasting seven days’): from late Latin hebdomadalis, from Greek hebdomas, hebdomad- ‘the number seven, seven days’, from hepta ‘seven’.