Hair types are generally categorized into four main groups: straight, wavy, curly, and coily. Each type is determined by the shape of the hair strand and its natural texture. Straight hair has a smooth surface and tends to be shiny, while wavy hair forms gentle waves and has more volume. Curly hair features tight curls or ringlets, and coily hair has very tight, zigzag patterns. Within these categories, hair can also vary in thickness and porosity. Fine hair is thin and delicate, while thick hair is coarse and robust. Porosity refers to how well hair absorbs moisture, which can affect styling and care routines. Understanding your hair type helps in choosing the right products and techniques for maintenance.