What is one of the dictionary types called?

A dictionary is a listing of words in one or more specific languages, often arranged alphabetically (or by radical and stroke for ideographic languages), which may include information on definitions, usage, etymologies, pronunciations, translation, etc. or a book of words in one language with their equivalents in another, sometimes known as a lexicon. It is a lexicographical reference that shows inter-relationships among the data.

An explanatory dictionary or monolingual dictionary is a dictionary that gives additional information, e. g. on pronunciation, grammar, meaning, etymology, etc. Such dictionaries are usually meant for the native speakers of the language.

The oldest known dictionaries were Akkadian Empire cuneiform tablets with bilingual Sumerian–Akkadian wordlists, discovered in Ebla (modern Syria) and dated roughly 2300 BCE. The early 2nd millennium BCE Urra=hubullu glossary is the canonical Babylonian version of such bilingual Sumerian wordlists. A Chinese dictionary, the c. 3rd century BCE Erya is the earliest surviving monolingual dictionary.