Linked from
The 45 pages that link to Functional group, each with the reason it gives.
SteroidRelated: Small changes to attached groups help distinguish one steroid from another.
Organic compoundRelated: Functional groups distinguish compounds with similar carbon frameworks.
Ion-exchange resinRelated: Ion-exchange sites are functional groups attached to the polymer matrix.
DiolRelated: The two hydroxyl groups define the characteristic chemistry of a diol.