Polysemy is defined as a phenomenon where a single linguistic unit has several yet related meanings (Evans and Green 2006). Using the Cognitive Linguistics Approach, this paper analyses the polysemy of two Gikũyũ body part terms namely kĩongo ‘head’ and gũtũ ‘ear’ .Cognitive Linguistics interprets the meanings of polysemous words based on their cognition as the identification of polysemy involves the conceptualization of everyday life. The body part terms are often used to talk about other things than body parts and show a great variety of meanings. This paper also shows that these body part terms have enormous potential for semantic extensions into other semantic domains. These semantic extensions have a clear motivation through either metaphor or metonymy which are central to Cognitive Linguistics.