question mark
Noun
Meaning
a punctuation mark (?) placed at the end of a sentence to indicate a question
Source: WordNetSynonyms
Hypernyms
Examples
In all affairs it's a healthy thing now and then to hang a question mark on the things you have long taken for granted.
A tired exclamation mark is a question mark.
It meant nothing to him any longer, only a faint tinge of sadness--and somewhere within him, a drop of pain moving briefly and vanishing, like a raindrop on the glass of a window, its course in the shape of a question mark.
The reason there's a question mark on my front door is just in case I forget my address.
Whenever I start a novel, I'm always looking for two things: a bit of science that makes me go 'what if?' and a piece of history that ends in a question mark.
Sex is a big question mark. It is something people will talk about forever.