What is Integral?

I know what an Integral Tender is, because I was there during EI.

I was talking today to someone who asked "why don't we use the term "Complete?"

I scratched my head, and began searching. The closest I could find was in the CME Group, where there is the term "All-or-None"

https://www.cmegroup.com/clearing/trading-practices/all-or-none.html 

Trading Practices: All-Or-None Orders - CME Group

All-or-None (AON) orders are orders executed in the open outcry venue that must be filled in their entirety at a single price. AON transactions are permitted only in certain products and must be for a quantity that meets or exceeds the exchange-specified AON
 minimum quantity for that product.

www.cmegroup.com

And also this (which has a nice discussion of the effects fo such tenders):

https://www.investopedia.com/terms/a/aon.asp

SO why don't we use the term All-or-None

All Or None (AON) Definition - Investopedia

All or none (AON) is an order type with the instruction to fill the order completely or cancel it; partial fills are not allowed. AON orders usually take longer to execute than normal orders ...

www.investopedia.com