1) The verb meant to make level or smooth and it occurs in the inventories of goldsmiths, in contexts which suggest that metal was flattened on a small anvil by blows from a special hammer.
1374 unum planyssch stythy, York
1458 j planysshing stithy et j planysshing hamer, York
1490 De v lez planeshyng hamers xijd, York. The term remained in use and can be found in cutlery records: 1766 all that newly erected mill now used for planishing, Sheffield.