This olive trilingual dictionary on the olive tree, with 440 pages in three languages Arabic, English and French, covering approximately 2,350 terms or entries in each language, is considered the first dictionary specialized in this field and unique in its genre and vocabulary. It aims to provide, among other things, complete knowledge and scientific service on the history, propagation and planting of this blessed tree, on the production and processing and pickling and its oil production, refining, therapy, and its pomace and wastes valuation and use in various aspects of life. The content of this document has been presented in the form of three dictionaries: The first used words or expressions in the Arabic language; the second, the words or expressions in French and the third, the words or expressions in English as terms of reference subject to translation. The document is completed with a list of bibliographical references and appendices reserved for the listing of the main organizations or associations related to the olive oil field as well as to the acronyms among the most encountered in the olive oil field. This work aims to bring satisfaction to the reader or researcher, in particular Arabic, whether in the Arab Maghreb countries where French is the second language or in the Arab Mashreq countries where English is the second language.