Ran across little Richard in verse (6)
I believe the answer is:
metric
'ran across little richard in verse' is the definition.
I can't judge whether this definition defines the answer.
'ran across little richard' is the wordplay.
'ran across' becomes 'met' ('meet' can be a synonym of 'run across').
'little richard' becomes 'ric'.
'met'+'ric'='METRIC'
Can you help me to learn more?
(Other definitions for metric that I've seen before include "System using litre and gram as units" , "Consisting of verses; pertaining to one system of measurement" , "Like some feet" , "System of weights and measures" , "Relating to verse - based on the metre" .)