In history, nothing to take abnormal pride about (6)
I believe the answer is:
period
'in history nothing' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'take abnormal pride about' is the wordplay.
'take' becomes 'o' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'abnormal' is an anagram indicator.
'about' means one lot of letters goes inside another.
'pride' with letters rearranged gives 'perid'.
'o' put into 'perid' is 'PERIOD'.
'to' is the link.
Can you help me to learn more?
(Other definitions for period that I've seen before include "Phase" , "Span of time" , "term" , "Time allocated for lesson in school" , "End of story" .)