/'saɪərən; `saɪrən/
n
1 device that makes a long loud sound as a signal or warning 汽笛; 警报器
*an air-raid siren 空袭警报器
* a police siren 警察用的警报器
* an ambulance/a fire-engine racing along with its sirens wailing 响着警报器急驰而过的救护车[消防车].
2 (in Greek mythology) one of a number of winged women whose songs lured sailors to their destruction （希腊神话中的）塞壬（半鸟半女人的怪物, 常用美妙的歌声引诱航海者触礁毁灭）.
3 woman regarded as fascinating and dangerous 妖艳而危险的女人.

n[C]
[Date: 1300-1400; Language: Old French;Origin: sereine, from Latin siren, from Greek seiren;]
[Sense: 1; Origin:French sirène, from Old French sereine]
a piece of equipment that makes very loud warning sounds, used on police cars, fire engines etc
　the wail of the ambulance sirens
　I heard police sirens in the distance.
siren voices/song/call
literary encouragement to do something that seems very good, especially when this could have bad results
　siren voices calling for the sale of weapons to the region
a woman who is very attractive but also dangerous to men - used especially in newspapers
　a Hollywood siren
the Sirens
a group of women in ancient Greek stories, whose beautiful singing made sailors sail towards them into dangerous water