What is Compendium?

Legal Definition
A compendium (plural: compendia) is a concise compilation of a body of knowledge. A compendium may summarize a larger work. In most cases the body of knowledge will concern a specific field of human interest or endeavour (for example: hydrogeology, logology, ichthyology, phytosociology or myrmecology), while a general encyclopedia can be referred to as a compendium of all human knowledge.

The word compendium arrives from the Latin word "compenso", meaning "to weigh together or balance". The 21st century has seen the rise of democratized, online compendia in various fields.
-- Wikipedia
Legal Definition
An abridgment, synopsis or digest
-- Black's Law Dictionary