Cold process soap making. What does that actually mean?

The art of soap-making can be traced as far back as ancient Babylon.
2800 B.C., archaeologists first discovered a soap material inside clay cylinders Inscriptions on the cylinders described a process of fats boiled with ashes, the very first soap-making method. But the Babylonians weren’t the only ones who benefited from this idea. Today, the cold process method of soap-making evolved to rely on a different ingredient called sodium hydroxide, commonly known as lye.
The world’s best soap makers use the cold process method.
Savon de Marseille was one of the best-kept secrets of southern France, and only in recent history have these artisanal soaps found their way to other parts of the world. Its superb qualities are praised for gently nourishing and cleaning the skin. This is because each ingredient is carefully sourced, and the process is fully controlled from beginning to end.
An effective handcrafted soap can be made by using the finest ingredients from your own kitchen pantry or homegrown herbs from the garden. Homemade soaps using the cold process method make a great project for using an abundance of aromatic and antibacterial herbs such as rosemary, sage, thyme, and oregano. But also, roses, lilac vanilla, or lavender add an amazing irresistible scent to your soap.
The cold process method is ideal for preserving the benefits of plant-derived oils and butter. The soap is long-lasting, as it does not get exposed to high heat levels and chemicals that can reduce lifespan.
Cold process soap contains oils and fats from plants, and it has a much higher fat content than other soaps, which means that it is also more moisturising. In this process, different oils like shea butter or almond oil are combined with lye to produce solidified soap. Lye technically refers to sodium hydroxide, which is a very caustic chemical that produces dangerous fumes so it is important to wear protective clothing and work in a ventilated room or outside. The saponification generally takes about 24 to 48 hours to complete once the lye and oils have been mixed and the raw soap has been poured into their form. Afterward, it should be left to air-dry for approximately four to six weeks; this is known as the curing time and it will allow for any excess water to evaporate out of the soap. After this so-called healing time, only the best ingredients are left in the soap and all chemicals are gone, that could harm your skin.