From Longman Dictionary of Contemporary Englishtittertit‧ter /ˈtɪtə $ -ər/ verb [intransitive] LAUGHto laugh quietly in a high voice, especially because you are nervous At the word ‘breast’, some of the class tittered. —titter noun [countable]→ See Verb table
Examples from the Corpus
titter• As the teacher read the poem someone tittered.• The crowd tittered, but he looked at them and silenced the titters.• People riotously reel around here, fighting, fondling, tittering, clowning.• This caused some of the other children to titter, quickly putting their hands over their mouths to stifle the sound.• On the edge of the crowd a few young men tittered, whistled, applauded and stamped their feet.Origin titter (1600-1700) From the sound 