名词

1. 运河;水道;沟渠
A canal is a long, narrow stretch of water that has been made for boats to travel along or to bring water to a particular area.

2. (人体内输送食物、空气等的)管,道
A canal is a narrow tube inside your body for carrying food, air, or other substances.

1. long and narrow strip of water made for boats or for irrigation

2. a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance

e.g. the tear duct was obstructed
the alimentary canal
poison is released through a channel in the snake's fangs

Synonym: ductepithelial ductchannel

3. (astronomy) an indistinct surface feature of Mars once thought to be a system of channels
they are now believed to be an optical illusion