The work Lingwai daida (Notes from the Land Beyond the Passes), written by Zhou Qufei in 1178, is one of the most important Song works dealing with China's maritime contacts with foreign countries and may thus be regarded as an important milestone in the field of geography. This article focuses on the historico-linguistic analysis of two toponyms used by the author in this work: Bosiguo and Kunlun Cengqiguo. Compared to the other toponyms mentioned in Lingwai Daida, these two are characterized by some special features. Although, according to Zhou's description, they were located within the same sea, the Xinanhai (Southwestern Sea), their characteristics are quite different, and so the exact identification of these two toponyms is still under discussion. Through the translation and the analysis of their description, this paper aims to underline the influence of the Arab geographical concept of the world on Zhou Qufei's work, in order to add a fruitful contribution to the research on historical contacts between the Chinese and the Arabs, in particular regarding the sharing of a concept of geography, which doubtless took place along the Maritime Silk Road over many centuries.