I am organizing a seminar but i wonder how to address the person who presents the presentation in that seminar. presenter or speaker? What is difference between presenter and speaker? Are they interchangeable?
Speaker is the correct word.
Note: In context of seminars, presenter and speaker have the same meaning i.e. the person who gives the discourse. However, the word "presenter" may give an impression that the speaker is presenting on behalf of someone else; for instance a proxy for the original researcher or the first author.
While I think one could safely use the words "speaker" and "presenter" interchangeably in the given context, there are, as usual, shades of meaning involved with each term that should not be ignored completely.
I agree with Blessed Geek's assertion that a presenter presents a presentation, which usually includes visual aids, and which may or may not allow for audience feedback; while a speaker speaks a speech, and speeches are usually non-interactive, non-visual affairs.
However, I would make the case that even a speaker who does nothing but read a speech is still technically a "presenter"--he's presenting that speech to the audience. A presenter, meanwhile, could theoretically not speak at all, perhaps merely gesturing at his or her visual aids. So no, the words are not completley interchangeable, but unless your seminar is about avant garde performance art, they're pretty darn close.
Normally we use presenter, when a presentation is involved, where the presenter is not simply just speaking on and on and on. Especially when charts, diagrams and audiovisuals as well as demos are involved.
It is untrue that "presenter" correlates strongly towards "presenting for someone else", because a speaker could just as easily "speak for someone else".
The presentation of the new software was done very well. The presenter was none other than the engineer architecting the software.
After reviewing a few practical examples, shown below, I support that Speaker is the person's role when delivering seminar or conference presentations.
Exceptions include presentation of published papers, such as SPIE conferences, where the participants are referred to as authors or presenters.