ˈMars Bar BrE AmE ( also Mars ) trademark
a popular type of chocolate bar with a centre made of soft ↑ nougat and ↑ caramel . Mars Bars are sold in the UK and the US, but American Mars Bars also have ↑ almond s in them. An old advertisement for Mars Bars used to say that ‘A Mars a day helps you work, rest, and play’.