Proposal and Transaction
Understand the shared Human view around one exact Stellar transaction.
A Transaction is the thing Stellar can execute.
A Proposal is the shared MultiSig Tools view that lets people understand, sign, submit, and later inspect that exact transaction.
Transaction
The exact Stellar operations, source accounts, preconditions, memo, fee, and signatures that can be submitted to the network.
Proposal
The Human collaboration surface around that transaction: Review, signatures, status, History, and retained evidence.
The Proposal follows the transaction rather than one person's browser or one Treasury. That is what allows independent signers to coordinate without sharing custody.
Technical details
The server-side coordination record is called a Request. Request is an API/storage term; Proposal is the Human product term.