A hairstyle, hairdo, or haircut refers to a styling of head hair. The fashioning of hair can be considered an aspect of personal grooming, fashion, and cosmetics, although practical considerations also influence some hairstyles.

Physical styling

Hair styling is a major world industry, from the salon itself to products, advertising, and even magazines on the subject. Hair dressing may include cuts, weaves, coloring, extensions, perms, permanent relaxers, curling and any other form of styling or texturing.

Length and trimming

Hair cutting or hair trimming often involves creating and maintaining a specific shape and form. Haircuts can be used to define a hemline along the ends and edges of longer hair. Hair cutting may include shaving the head. In some settings, hair cutting, creating forms and shapes are an expressive art form. Hair cutting often involves considerations of body proportions, hair density and hair type, face and head shape from all views (profile, 3/4 and 360 degree, from above and from below), overall bone structure, and pattern of how hair lies or falls. hs are often derived from concerns regarding personal expression and aesthetics (examples: dreadlocks, punk hair, the business haircut/style, very long hair), religion (for example, Pentecostal faith among others), social and cultural values. Hair is often a physical expression of one's sense of self, of a desire to present oneself to and amongst a community, of social status and roles, and of cultural values. Such expression may involve adding ornaments to the hair, or partial or full hair coverings (such as a Kippa, Hijab, or a Turban).

Although trimming may beautify hair by removing damaged or split ends, cutting does not promote faster growth. Nor does trimming remove all damage throughout the hair. Damage can occur anywhere in any length of hair. Trimming at regular intervals is only necessary for maintaining formed shapes.

There exist ways to trim hair oneself as outlined in places on the internet and hair care reading materials.

Wet hair stretches rather significantly in length. Curly hair will unfurl a fair amount when fully wet, and different areas of the hair may have a larger degree of curl or different direction of curl than others. Thus, cutting curly hair while wet may result in uneven lines or unexpected results with regard to actual length. Further, curly hair, in particular, once dry, might appear visually to have an uneven line depending on how the curl coils back up. Lorraine Massey, author of Curly Girl, specializes in the care of curly hair types, and has designed a specific method for trimming curly hair to avoid these problems. The reason stylists like working with wet hair may be related to weight. Wet hair is heavier and may be easier to manage in a cut/style situation since the hair remains in place thus holding a line and making it easier for the stylist to create a form.