I think he may mean it has been run through a planing machine and is square and clean but not finished. From memory (I used to do this stuff between ages 12 and 20) the planks from the saw mill are run through the planing machine just to knock off the rough stuff and squared off.
If you wanted to go further you would do multiple runs through the planing machine untill the wood was smooth and at final dimensions.
Is my memory holding up woodworkers?
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