What is a Portrait?

I'm looking for a definition of a portrait, in the context of what one might enter in a photographic competition.

There has been some discussion over the boundaries between portraiture and reportage - does, for example, a picture of three people sat at a cafe table constitute a portrait? Can you have a portrait of a pet dog or cat, or does the subject have to be human?

Any thoughts would be appreciated.

Interesting, I tend to think of a portrait as 'still life' and as such, it could be an inanimate object - taken somewhat out of context and therefore isolated from it's surroundings.
A group shot would not in itself be a portrait but rather a collection of individual portraits although the emphasis would have to be on the group.
For me, a portrait should be of a single person or object so composed as to totally draw the viewers attention to the subject.
It could be argued that any photograph, being a frozen moment in time, is a portrait but I think a static pose would qualify better than a deliberately blurred image that emphasizes movement.

An example of a perfect portrait (by my definition) would be a close-up image of part of an object such that you feel the need to really study the image in order to identify the object. Or it could simply be a classic 'head and shoulders' person shot or a building - anything that doesn't require a background setting.

As far as I'm concerned, a portrait should capture some of the essence and personality of the subject. For example, your passport photo is just that - a photo. It's functional and objective. A portrait, on the other hand, "portrays" a whole lot more about it's subject; it is, therefore, subjective.

FWIW

In my opinion, a portrait is traditionally regarded as some image, photographic or other , of some existing being ,or thing, living or deceased. You could have a portait of an animal, an object, or a thing. Sometimes a portrait can express multiple levels of artistic intention, or no intention other than one of utility, such as the passport photo. Then it is not art, unless it is intended as such.

In art there are a lot of ahhh, ... exceptions to rules, but generally
if you look at curent calls for photo entries, say in many of the leading photo mags, the criteria are arranged by catagory.

I can say this much for sure : If i take a photo of myself then that is a self portrait. If i take a photo of you then that is a portrait of yourself, taken by myself, which makes it a portrait of you , and that is still a self portrait even though you did not take the photo yourself. In that case i could come on board here and query you as to the best portrait lens, knowing that strictly speaking, no such lens exists. Or does it?