The term 'plaster tool' refers to two tools used in the application of plaster, a material used for coating walls and ceilings. The first tool is a TROWEL, which is a flat, rectangular-shaped tool with a handle used to spread and smooth plaster. The second tool is a spatula, which is a thin, flat tool with a handle used to scrape and shape plaster. Both tools are essential for achieving a professional finish when applying plaster.