petrol blue

== English == === Noun === petrol blue (UK) A greyish blue colour, tinted with green. ==== Usage notes ==== Many people erroneously believe that this is a misspelling of petrel blue, and that the term refers to the sea bird. However, the OED gives only this spelling. The term may originally have pertained to petrol-derived compounds such as paraffin, which is often coloured blue. === Adjective === petrol blue (UK) Of a greyish blue colour, tinted with green. === See also ===