The definition of an institution is an established custom or practice, or a group of people that was formed for a specific reason or a building that houses the group of people. Marriage is an example of a cultural institution.
Contextual targeting is a type of targeting on the Google Display Network in which you select specific keywords or topics and then allow AdWords to identify websites that are a good fit for your keywords and targets.
Contextual tabs are tabs that appear only when the user needs them. For instance, in a word processor, an image-related tab may appear when the user selects an image in a document, allowing the user to interact with that image. The usage of the term ribbon dates from the 1980s and was originally used as a synonym for what is now more commonly known as a (non-tabbed) toolbar.