Clear cuttings refers to the visual quality of the wide face or faces of a board involving assessing the number of visible faults and the length and width of clear cuttings that can be won out of a board. Systems, rules and categorising the boards varies from country to country or region to region. The American Appearance Grading system is one grading system, as is The French Timber Association system for allocating visual characteristics.
Essentially clear cuttings is a term for a visual appearance assessment of a board and really has nothing to do with assessment for a board's strength. Using the term clear cuttings as a descriptor for a board is generally a bit meaningless without it being linked to grading criteria, e.g., if buying what are classed as FAS (First and Second face) boards in the American Appearance Grading system the FAS rules specify the minimum length and width of fault free clear cuttings (knots, etc) permissible in a board. Slainte.