No, lactose is not a polysaccharide; it is a disaccharide. Lactose is composed of two simple sugars, glucose and galactose, which are linked together. Polysaccharides, on the other hand, are large molecules made up of many monosaccharide units, typically more than ten. Examples of polysaccharides include starch, glycogen, and cellulose, which serve various functions in living organisms, such as energy storage and structural support.
In summary, because lactose consists of only two sugar units, it classifies as a disaccharide, distinctly different from the complex structure of polysaccharides.