The authors argue for a rapprochement between cognitive linguistics and semiotics in metaphor research, given that similar issues are discussed, related to conventionality, context-sensitivity, cross-cultural variation, creativity, and different semiotics systems (mistakenly called "multimodality"). The point is made with for focus on metaphors in Greek street art, analyzed from the perspective of cognitive semiotics. Using the Motivation and Sedimentation Model (MSM), which distinguishes between three interacting levels of meaning making: the embodied, the sedimented, and the situated, the authors suggest a new definition of metaphor as sign use based on experiencing one thing in terms of another, giving rise to both tension and iconicity between two different meanings. By reviewing a prior empirical study on unisemiotic and polysemiotic metaphors in Greek street art, the author argue that metaphoricity is ultimately a matter of situated and socio-culturally-sensitive sign use.