The Creative Commons world includes many buzzwords -- legal, social, and technical. Here's a quick guide to some of them, with links for more on each.

BY
The short name for the attribution term of CC licenses. "CC BY" is a CC license that only requires giving credit -- allowing commercial and derivative use.
CC+
A protocol describing the offering of a work under a CC license plus other options, such as the availability of private agreements that provide permissions or warranties beyond the scope of the CC license on offer. Note that one cannot add restrictions to a CC license via this or any other mechanism.
CC0
A waiver that attempts to offer users as many rights as possible, currently in beta.
ccHost
A remix-oriented content management system that powers ccMixter, licensed under the GPL.
CCi
Creative Commons International refers to the project to legally and linguistically "port" CC licenses to jurisdictions around the world and the global network of teams engaged in this and follow-on activites.
ccLearn
A division of Creative Commons that works to minimize legal, technical and social barriers to reuse of educational materials.
ccMixter
A remix-focused music community developed by Creative Commons to demonstrate the creative re-use of openly licensed music.
Copyleft
Usually refers to a license that requires distributed modifications of licensed works be shared under the same license, most prominently in the case of the GPL. CC calls this property of licenses ShareAlike. CC BY-SA is unambiguously a copyleft license, while some consider CC BY-NC-SA to not be in the spirit of copyleft.
Copyright
A right automatically granted to authors to prevent others from using their works without permission for a very long time and with limited exceptions. The expansion of copyright in length and scope with the increased costs of copyright enforcement in the digital age are some reasons Creative Commons exists.
ccREL
Creative Commons Rights Expression Language, a composite recommendation of technologies for marking digital media with license information and other metadata.
Fair Use
The right to make certain uses of a work without permission of the copyright holder.
Free Culture
The name of a movement of which CC is a part, a book by Lawrence Lessig, and Students for Free Culture. The Definition of Free Cultural Works specifies which licenses its authors believe qualify as free culture licenses -- CC BY and CC BY-SA qualify, while licenses with NC or ND terms do not.
Jurisdiction
A legal system. The CCi project "ports" CC licenses to individual jurisdictions. Often a jurisdiction is the same as a "country" but in some cases there is more than one legal system within a country or disagreement about exactly what legal systems and corresponding geographies make up a country, so we use the term jurisdiction for maximum accuracy.
liblicense
A software library in the C programming language that makes functions such as reading and embedding license metadata and discovering license properties available to other programs.
NC
The short name for the NonCommercial term of some CC licenses, often used by itself to refer to the term in any of these licenses or as part of their short names, e.g., "CC BY-NC".
ND
The short name for the NoDerivatives term of some CC licenses, often used by itself to refer to the term in any of these licenses or as part of their short names, e.g., "CC BY-NC-ND".
OA
Open Access
OER
Open Educational Resources. OER are educational materials and resources offered freely and openly for anyone to use and under some licenses to re-mix, improve and redistribute.
Public Domain
Works that are not restricted by copyright either because they are very old or not copyrightable (e.g., data).
RDF
Resource Description Framework, a model for representing statements about things on the web. CC uses RDF to model license properties and describe licensed works.
RDFa
RDF in attributes, a mechanism for annotating web pages such that machine-readable data is colocated with human-visible markup, allowing metadata to be retained through operations like copy and paste. The key recommendation of ccREL.
SA
The short name for the ShareAlike term of some CC licenses, often used by itself to refer to the term in any of these licenses or as part of their short names, e.g., "CC BY-SA".
Science Commons
A division of Creative Commons that applies open tools to the problem of unlocking the value of research so more people can benefit from the work scientists are doing.
Semantic Web
The project to make the web machine-readable using technologies such as RDF.
Some Rights Reserved
A descriptive tagline for any CC license -- the licensor offers some rights to the public, but withholds others.
Unported
Since version 3 of the CC licenses, "unported" licenses are those written with reference to international treaties in language recognized globally to the extent possible, as opposed to "ported" licenses with language written to be familiar to copyright law in a particular jurisdiction.
XMP
eXtensible Metadata Protocol, a format for embedding metadata in many different file formats, most significantly PDF and JPEG. A recommendation of ccREL.