This thesis will analyse a sample of maritime terminology used along the Saudi Red Sea coast and attempt to understand why lexica are lacking in such terms; an issue which can be linked to the language change was a consequence of the interaction between Arabs and other ethnic communities since the advent of Islam. This change raised alarm among lexicographers and linguists at the time of documenting the terminology, who set off on long journeys to collect the pure language. In their word collecting they selectively documented the language, ignoring a huge amount of spoken registers because their aim was to collect the classical form of Arabic in order to help Muslims gain a deeper understanding of the Qur>[n and |ad\th. This created gaps in Arabic lexicography, which lacks terminology for material culture. The information about maritime material cultural terminology in the mainstream lexica is disappointing. Although a few terms are listed, lexicographers have failed to provide unambiguous definitions. This study demonstrates why a great number of such terms since the classical time period has not been listed in the available lexica, and what the factors are which led to this situation. Hence, this study is based on maritime terms extracted from informal meetings I had with mariners and fishermen on the Red Sea Saudi coast about their life at sea before the introduction of the engine to vessels. The collected terms are to be investigated against their presence in lexica both synchronically and diachronically. Understanding the meanings of such ignored terms is one of the most important puzzles and this study attempts to solve it by investigating the semantic links between words and the conceptual meanings of their roots following a hypothesis based on Ibn F[ris (d. 395/1004); which assumes that all terms derived from Arabic roots should share a general conceptual meaning. While in the absence of maritime terms in lexica a hypothesis devised from Agius's theoretical framework was applied to search such terms in literary and non-literary works, which assumed to be an alternative source to lexica and examine their occurrence in text and context by reconstructing their origin, function and use.