1. Lavaliere

The kind of microphone that clips onto one's shirt near the neck and has a power pack that clips on at the waistline.  This leaves your speaker's hands free to be more comfortably articulate, to handle any props, and to advance PowerPoint slides.

2. Lectern

The correct name for the furniture item that one stands behind when introducing a speaker.  Notes can be placed on the lectern and, in some cases, a microphone is built in.  They are often commonly mistakenly called "podiums".  In reality, podium refers to the raised stage area that one might be standing upon - whether or not a lectern is on the podium.

3. ROI

Return On Investment - what the client hopes to get out of the keynote.  This generally refers to financially but is also used to refer to softer gains, like a more congenial work environment, better safety, or legal compliance.

4. One-Sheet

The brochure of choice in the speaking industry is a single sheet expression of what the speaker does overall.  They may be single or double sided.

5. Spec(ification) Sheet or Program Sheet

A separate page on a specific program that might be the right fit among the speaker's offerings.

6. Proxima (LCD projector)

A device that takes a laptop's screen and projects it onto a screen for all to see.  Proxima is only one name brand of LCD projector but, like Jell-o and Xerox, sometimes a name brand becomes the word people tend to use for it.