Space in musical semiosis examines key issues of musical signification. It employs C. S. Peirce's semiotics and cognitive metaphor theories to establish a theory of the musical composition process, an epitome of musical signification. Music signifies by virtue of two kinds of metaphors in thought-signs. Conceptual metaphors represent situations of the world. Musical metaphors join musical situations with those of possible words due to their similarities as conceptual spaces. To compose music is to construct metaphors, to produce and experience possible situations mediated by sounds and its quality dimensions. Music is meaningful as it provides means of working out actual and possible situations of life.