What is to laugh with the tongue striking against the root of the upper teeth; to laugh with restraint, or without much noise; to giggle. A group of tittering pages ran before. Longfellow called?

titter — To laugh with the tongue striking against the root of the upper teeth; to laugh with restraint, or without much noise; to giggle. A group of tittering pages ran before. Longfellow. (Webster's 1913.)

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