This article deals with the semantics of the Turkish lexemes: iç and içeri, related to the internal part, internal space, or the contents of an object; dış and dışarı, correlated with the external part, the surface of the object, and with everything that surrounds it from the outside. Their morphological, syntactic, and compatibility features were considered. The relevance of the research carried out using the corpus method stems from the fact that lexical semantics (in the broad sense of the term) is one of the priority areas of modern linguistics because it studies the conditions for the correct construction of statements that are not determined by grammatical and syntactic norms. The analysis yielded the following results: the four lexemes under study are typically used with possessive suffixes when they perform the nominal function; the presence of ancient indicators of directionality in içeri and dışarı underlies their predominant use in the adverbial function; the very high frequency and wide lexical compatibility of the lexemes iç and içeri arise from the key role played in the linguistic consciousness of Turkish speakers by the idea of the internal space/filling of objects as a special entity that determines the state and possibilities of using the object. For the space external to the reference point, on the contrary, it is not a description of its state that is important, but a more accurate indication of the position of objects, which is associated with the possibility of reaching them and is enabled by the presence of a clearly structured system of tokens with spatial meaning. This is expressed in the lower frequency of the lexemes dış and dışarı and the formation of the meaning ‘outside’ in the possessive-marked postposition function. The conclusions obtained are of both practical importance for teaching the language and can be efficiently used as a promising material for typological lexico-semantic research, especially in what concerns the directions of development of the vocabulary of the Turkic languages.