User provided inputs to the blockchain that instruct what the State Transition Function should do.
This keyword borrowed from the database industry. A more general form of it is Signed Extrinsic Data, borrowed from the Polkadot jargon.
The keyword transaction is very popular, yet it is mostly used when a user signs some information, sends it to the block authors to be included in a future block (see Journey of a User Transaction). This jargon is enough for simpler blockchains that only allow this one type of transactions in their STF. Yet, it is insufficient to describe:
- What if the input was not signed by a user? This is mainly why Polkadot chose the broader term Extrinsic as opposed to Transaction.