You Know what I Mean?

Does a word mean what it says? Sometimes - but not always. Everyone thinks that meaning is contained within words - like sardines in a tin, or milk in a bottle. After all, words are nice stable things that you can look up in a dictionary aren't they? But dictionaries only take us so far... If you eavesdropped on a teenage conversation, rushing to a dictionary - with its definitions frozen in time - wouldn't help much.