The term 'CERTAIN PENS' can be broken down into two crossword solutions: BICS (4 letters) and FOLDS (5 letters). BICS stands for 'Ballpoint Ink Cartridge System', which is a type of pen that uses a replaceable ink cartridge. FOLDS stands for 'Fountain-Oriented Liquid Dispensing System', which is a type of pen that uses liquid ink. Both types of pens are popular for writing, drawing, and other activities.