There's so much confusion surrounding what a "headshot" actually means. To a photographer, a headshot is just that, a photo of the head and shoulders, like the tight crops you're used to seeing on LinkedIn. Headshots are typically used for business purposes to promote yourself professionally and are most often photographed with a smiling, friendly expression. Actor headshots have more freedom in the expression they choose depending on the role they are trying to attract, be it comedy, drama, etc.
Portraits are different from headshots in that they usually incorporate more of the body into the frame and are more stylized. This is where skilled posing and an experienced photographer can really shine. The subject needs to look relaxed and at ease while flattering their unique body shape. Portraits take more time to create because there are more moving pieces of the puzzle that have to be perfect in order to create one winning image. The pose, hand placement, proper wardrobe draping, in addition to the standard headshot checklist: hair placement, light intensity and direction, and coaching a great expression out of your nervous client.
Non-photographers often refer to portraits as headshots. So to adapt to their language, photographers also started referring to portrait images as headshots. As photographers, we only know what you're actually meaning because we ask questions. How will you be using your images? What types of marketing, if any, will you be doing with your images? What is the feeling you want to portray in your images? Do you have samples of photos you've found online that you absolutely adore? What is it about those images that draws you in?
As you can see from the sample images here, the differences between what defines a headshot and a portrait are subjective and subtle. In the end, the nomenclature that you use when referring to your images doesn't matter one bit.