from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Chiefly British A rubber-soled cloth shoe; a sneaker.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A rubber-soled lace-up canvas shoe for sports or onboard ships; a precursor of trainers.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a light gym shoe with a rubber sole and a canvas top
- n. waterlines to show the level the water should reach when the ship is properly loaded
Probably from the resemblance of its mudguard to a Plimsoll mark.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Samuel Plimsoll, a Bristol merchant. (Wiktionary)