Yeah, essentially you got it right. Transactions are a type of operation. Essentially, when it comes to blockchain, there are two categories of operations, read and write. A transaction is a type of write operation. An example of the use of a read operation would be pretty much any block explorer, because it's finding out what the data is, but it isn't changing it or updating it in any way.
Here's a pretty good article that explains it:
https://hackernoon.com/blockchains-versus-traditional-databases-c1a728159f79
