open question

British  

noun

1. a matter which is undecided

2. a question that cannot be answered with a yes or no but requires a developed answer

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open question Idioms  

1. An unresolved issue, one that has not been finally determined. For example, Whether the town should pave all the unpaved roads remains an open question. In the mid-1800s this term acquired a specific meaning in the British Parliament, that is, “an issue on which members may vote independently, without respect to their party affiliation.”

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Example Sentences

How convergence would occur remains an open question.

From Barron's

"It's striking that foams and modern AI systems appear to follow the same mathematical principles. Understanding why that happens is still an open question, but it could reshape how we think about adaptive materials and even living systems."

From Science Daily

What a military takeover of Greenland would mean is an open question.

From The Wall Street Journal

Where college football’s newest superstar goes next remains an open question.

From The Wall Street Journal

Whether Rodríguez will cooperate with the administration is an open question.

From Los Angeles Times