gatherings

Preferred label: 

A group of folded or single leaves which can be used either singly or with other gatherings to create a textblock. Gatherings may consist of printed, manuscript or blank leaves or combinations of these.

AAT

The Arts and Architecture Thesaurus Online, The Getty Research Institute.

Additional reference: 
http://vocab.getty.edu/aat/300194226 (modified)
Alternative label: 
sections
quires
Broader concept: 
Broader partitive concept: 
Top concept: 
objects