Tallow is a hard, pale fat that comes from rendering (melting down and purifying) the fat of cattle or sheep. For thousands of years, tallow was one of the most useful materials in daily life. People used it to make candles that lit homes before electricity, to make soap for washing, and to waterproof leather boots and saddles.

Tallow candles were the main source of light for ordinary people for centuries. They burned longer than many other materials and were affordable, though they sometimes gave off smoke and a smell. Wealthier families might use beeswax candles, which burned cleaner but cost much more.

Today, tallow still has uses: some soap makers prefer it for traditional recipes, and it appears in certain industrial products. Some cooks even use beef tallow for frying because it can handle high heat and adds flavor, though vegetable oils are more common now.

When you read historical novels or stories set before the 1900s and see characters making or buying tallow, you're glimpsing a world where people had to create their own light and soap from whatever materials they could find.