I. trill 1 /trɪl/ BrE AmE verb [intransitive and transitive]
1 . to make a short repeated high sound:
birds trilling in the trees
The phone trilled sharply.
2 . to say something in a high happy voice that sounds slightly false:
‘Have a nice time, darling,’ she trilled.
II. trill 2 BrE AmE noun [countable]
[ Date: 1600-1700 ; Language: Italian ; Origin: trillo , from trillare 'to trill' , probably from Dutch trillen 'to shake very quickly' ]
1 . technical a musical sound made by quickly moving between two notes
2 . a short repeated high sound:
the trill of blackbirds