hollow tube

• pipeHollow conveyance channel
• cylinderCircular-based solid form
• strawTube for sipping
• tunnelEnclosed underground route
• conduitTube conveying fluid or cables

barrel · shaft · bore · duct · channel · reed · catheter · hose · vein · artery · flute · bamboo · culvert · drainage · siphon · windpipe · snorkel · cannula