Information given us in class (5)
I believe the answer is:
genus
'class' is the definition.
(thesaurus)
'information given us' is the wordplay.
'information' becomes 'gen' (gen is a kind of information).
'given' says to put letters next to each other.
'gen'+'us'='GENUS'
'in' is the link.
(Other definitions for genus that I've seen before include "Part of the family" , "Taxonomic grouping" , "Group of plants with common characteristics" , "Kind or sort of" , "Biological group containing one or more species" .)