question mark
noun
ukus [ C, usually singular ]
a feeling of doubt about something:
a question mark over/about sth There is a big question mark over people's willingness to invest in this scheme.
The biggest question mark hanging over China's exports lies in the currency exchange rate.
[ C ] MARKETING
a product or company that has a small share of a market that is growing very fast:
If nothing is done to change the market share, question marks will just absorb large amounts of cash.
See also
cash cow
dog
star noun