Often (4)
'often' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for commonly that I've seen before include "What's very often" , "Not how the aristocracy behave" , "Usually, normally" , "as a general rule" , "Usually, ordinarily" .)
'often' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for decimal that I've seen before include "Using powers of ten" , "Relating to ten" , "Claimed, wrongly, to have this currency" , "fraction" , "(System) based on tens" .)