The heading applies only to the pure fractionated products — stearin and oil phases separated from lard or tallow — in their natural, unblended state. Once these fractions are emulsified with water, mixed with other fats, or incorporated into a compound preparation, they move out of heading 1503 and into the prepared-fats or food-preparations chapters.

Lard is the whole rendered fat from swine tissue, while lard oil is the liquid fraction obtained by pressing or chilling lard to remove the solid stearin. Lard oil has a lower melting point and is used in industrial lubricants and specialty food applications where a pourable fat is needed. The two products classify under different headings — lard under 1501 and lard oil under 1503.