I think it would be good if these two uses of "agglomerate" were more distinguished: feature agglomeration doesn't require agglomerative clustering, and is better placed under a dimensionality reduction discussion than under Hierarchical Clustering, IMO.

"Feature agglomeration" is also a term with very little currency in the literature -- a major exception being a paper from INRIA-based scikit-learn authors -- so its definition needs particular attention.