"Accounting period", as used in the finance industry and in business, means a month, a quarter, a fiscal year.
Accounting period can be any period. Accounting periods are not only those periods that are defined in IRS manuals... Every organization is free to define their own accounting periods to suit their internal needs. If you need reliable data for all financial transactions every minute then 1 minute can be the accounting period.
If you are familiar with the algorithm that miners run though, you'll know that's not the case.
Hmm... Well, I thought you have started this thread trying
to abstractly describe Bitcoin in as few words as possible with terms
that would make sense to those who are familiar with banking but not with technology? So, my short answer to your initial question is miners are like auditors and what they do is like reconciling data sets of financial transactions for 10 minute accounting periods.
I'm not sure the block finding duration is equal to any "accounting period". A transaction has a timestamp, that's when it should be considered to have been taken place. It can only be decided at a later point (with enough confirmations by miners) wether or not it took place.
On the transaction list my bank gives me, for example, there are two timestamps. One designating the point in time when the money flow was considered to be happening (relevant for calculating interest, for example) and the point in time the transaction was validated by or inserted into the system. The two can be different.