Question about consignments and shipments

Hello TSC,

I'm in the process of reviewing the definitions in the common library
and am now considering the ABIE "Consignment" (Consignment. Details).  I
note that a consignment (row 284) can contain multiple shipments (under
the name "Consignment. Consolidated_ Shipment. Shipment", row 344), but
I also note that every shipment (row 1672) can contain multiple
consignments (under the name Shipment. Consignment, row 1694).  This has
something to do with the notion of consolidation, but I can't figure out
what.

Are consignments collections of shipments, or are shipments collections
of consignments?  And what does this have to do with consolidation?

Jon