Externalise is a verb which means to make something external or to express something externally. MANIFEST is an 8 letter word which means to make something visible or to show something clearly. EXHIBIT is a 7 letter word which means to show or display something. EMERGE is a 6 letter word which means to come out or appear. EMBODY is a 6 letter word which means to represent something in a physical form. All of these words can be used to describe the act of externalising something.