See definition #2 here.
Does info(rmation) gap now make sense if you look at the following exercise in which A and B have to ask each other questions in order to fill in the gaps?
A has a sentence that reads: Peter _____ walked _____ his bedroom at ______ in the morning.
B has a sentence that reads: _____ Jones _____ out of his _____ at six o'clock in the _____.
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