Dictionary.net

• light carried by a boat that indicates the boat's direction; vessels at night carry a red light on the port bow and a green light on the starboard bow

2006 - WordNet 3.0
By Princeton University

• light carried by a boat that indicates the boat's direction; vessels at night carry a red light on the port bow and a green light on the starboard bow

2011 - English Dictionary Database
By DataStellar Co., Ltd