'Fifthly' definitions:

Definition of 'fifthly'

From: WordNet
adverb
In the fifth place; "fifthly, we must adhere to the rules set by the local government"

Definition of 'Fifthly'

From: GCIDE
  • Fifthly \Fifth"ly\, adv. In the fifth place; as the fifth in order. [1913 Webster]