Slovar slovenskega knjižnega jezika 16. stoletja (SSKJ16, 'Dictionary of Sixteenth-Century Slovenian') is a historical explanatory dictionary, featuring a complete inventory of semantic, stylistic, morphological, phonological, and often also syntactic examples of individual headwords. It is the most extensive and most accurate historical history of any period of standard Slovenian to date. The first volume (A–D) contains 3,027 entries, of which 2,061 are explanatory and 966 are cross-references. A total of 3,414 headword meanings are defined. The dictionary corpus comprises all Slovenian texts from preserved printed works by sixteenth-century Slovenian Protestant writers published between 1550 and 1595, as well as the Slovenian part of Hieronymus Megiser’s multilingual dictionaries (1592, 1603). This first volume of the dictionary has been compiled based on a card corpus (a total of 3,169,000 tokens), in which every word is presented in a contextual example. In the last stage, the volume was updated with the digital corpus Korpus 16, which contains transcriptions of forty-five literary works on 12,945 pages. Because the dictionary inventories the standard-language heritage of Slovenians from nearly five hundred years ago, it offers an important source of information for both the professional community and general users interested in when a specific word was first attested in standard Slovenian and what historical meanings it had.