sonar
noun
ˈsəʊnɑː
noun
1
equipment
on
a
ship
or
SUBMARINE
that
uses
SOUND
WAVES
to
find
out
the
position
of
objects
under
the
water
声呐（设备）〔船上或潜艇上利用声波探测水下目标位置的仪器〕