verb (intr, adverb)
informal (of a baby) to sleep all night without waking up
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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Idioms and Phrases with sleep through
Sleep without waking for a period of time, usually the night, as in At three months many babies have learned to sleep through. [Mid-1900s]
sleep through something. Fail to pay attention, as in We all slept through the explanation and then had trouble getting the machines started.
The American Heritage® Idioms Dictionary
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