This article discusses the sources used by the erudite in languages Albert de Biberstein Kazimirski (1808–1887) when he composed his bilingual dictionary Dictionnaire arabe-français, and especially two sources: The Lexicon arabico-latinum by Georg Wilhelm Friedrich Freytag (1788–1861), which was one of Kazimirski’s main sources, and through this latter on the lexicon of botanical and zoological designations found in the books authored by the Swedish naturalist Peter Forsskål (1732–1763). The article confirms that behind certain lexemes of natural history in Kazimirski’s dictionary lie these two sources, with Forsskål’s lexicon containing many words of Yemenite origin.