Attribution (BY) : “BY” refers to attribution. This means in order to use the work, you must attribute the author of the work. All of the Creative Commons licenses require this condition (CC0 does not, but according to the CC FAQs is it not a “license”).
Share Alike:Share Alike means that if you create an adaptation of a work that has this license, the adaptation must be licensed under the same or a compatible license.
NC: means that the work may only be used for non-commercial purpose. In NC licenses, non-commercial is defined as “not primarily intended for or directed towards commercial advantage or monetary compensation” (see, e.g., CC BY-NC 4.0). What matters here is the use to which the work is being put, not the user: one has to consider whether the use is for a commercial purpose, not whether the user is a commercial entity. A for-profit company could possibly use a work licensed CC BY-NC in a non-commercial way. In addition, using the work in a tuition-based educational course may still be considered a non-commercial use. The definition of “non-commercial” in these licenses is somewhat vague, and while some uses are clearly commercial and others clearly not, some may be in more of a grey zone. Find more information on how Creative Commons interprets non-commercial use on the CC Wiki.
No Derivatives (ND)
ND means that you cannot share an adaptation of the work, though you could use and share it in its original form. An example of an adaptation of an image would be changing its colour, blurring it, or adding another image on top of it. An example of an adaptation of a written work would be translating it to a different language. The points below, adapted from section 3.3 of the Creative Commons Certificate for Educators and Librarians, provide more details on what is and is not considered an adaptation:
Syncing a musical work with a moving image is an adaptation regardless of what applicable copyright law may otherwise provide.
Technical format-shifting (for example, converting a licensed work from a digital format to a physical copy) is not an adaptation regardless of what applicable copyright law may otherwise provide.
Fixing minor problems with spelling or punctuation is not an adaptation.
Reproducing and putting works together into a collection is not an adaptation of the individual works so long as they have not themselves been adapted. For example, combining stand-alone essays by several authors into an essay collection for use as an open textbook is a collection and not an adaptation. Most opencourseware is a collection of others’ open educational resources (OER).
Including an image alongside text, as in a blog post, a slide, or an article, does not create an adaptation unless the photo itself is adapted.