1
- a quavering or vibratory sound, especially a rapid alternation of sung or played notes颤音（尤指歌曲或乐曲中音符的快速交替）：
they heard the muffled trill of the telephone
他们听到了电话那边沉闷的颤声铃声
the caged bird launched into a piercing trill.
笼子里的鸟儿开始颤声尖叫。
1.1
- the pronunciation of a consonant, especially r, with rapid vibration of the tongue against the hard or soft palate or the uvula颤动辅音（尤指发辅音r时舌触硬、软腭或小舌的快速颤动）。
no obj.
1- produce a quavering or warbling sound发颤音：
a skylark was trilling overhead
一只云雀在空中啭鸣
with direct speech 'Coming sir,' they both trilled.“来啦, 先生,"他俩颤声尖叫。
1.1
- with obj. sing (a note or song) with a warbling or quavering sound用颤音唱：
trilling a love ballad, she led him to her chair.
她边颤声唱着情歌, 边引他到她的椅子旁。
1.2
- with obj. pronounce (a consonant) by rapid vibration of the tongue against the hard or soft palate or the uvula用颤音发（辅音）。
词源
mid 17th cent.: from Italian trillo (noun), trillare (verb).