n. — Geography
a shallow bay that abuts a lake or a stretch of a river.
Type: 3. Semantic Change — The term back bay is used to describe a shallow and quiet body of water (see the 2006 quotation) attached to a lake (see the 2014 quotation); accordingly, back bays are often discussed in contrast to "the main lake" (see the 1991 and 2005 quotations). A back bay is often a prime fishing location (see the 1988, 2000 and 2013 quotations). The term back bay does not appear in our non-Canadian dictionaries (e.g. DARE, OED).
See also COD-2, s.v. "back bay", which is marked "Cdn".
See also: slough (DCHP-1) meaning (2b, 2c, 3)
- 1959  Although it isn't quite the spunky fighter the smallmouth is, don't underestimate the largemouth bass for it can turn in a good performance on rod and line and usually runs a bit larger than its relative. The largemouth will live in warmer water than the smallmouth and haunt quiet back bays, weed beds and the like. It takes the same lures. 
- 1970  The Ontario Department of Lands and Forests announced yesterday that carp found floating in the Grand River at Galt last week died of natural causes rather than as a result of effluents in the water. A spokesman at the department's district office said the fish were probably caught in eddies and back bays and were frozen in or suffocated during the winter. 
- 1982  Inshore or back bay fishing means angling in rivers, inlets and places such as the estuarine shallows of Everglades National Park or the sheltered waters near Marco and the Ten Thousand Islands. 
- 1988  We tried our experiment in a back bay which has been known for an abundance of perch and pike. Three tipups with two hook each were set up close together in a triangle. 
- 1991  Our cottage is on a point at the narrows of our lake between the main lake and the back bay. On a windy day we sit and watch the sailors standing on their sailboards trying to navigate the narrows where the wind always blows. 
- 2000  It's true that carp do frequent the shallows. Right about now they're just finishing spawning in places like Last Mountain Lake. If you can find a shallow slough or back bay just off the main lake, muddy and full of weeds, sit quietly for a moment and watch. You'll see, scattered around the area, the back and tail fins of large carp sticking up out of the water. Count them and you'll know that you're looking at a significant number of fish. 
- 2005  We are in a quiet back bay, out of the strong wind that has made the main lake quite choppy. The bass aren't biting much, but we are catching some big perch, enough to satisfy my parents' diminished fishing expectations. 
- 2006  As a child, I always associated boating with wild places. We used canoes and kayaks to take us away from civilization to the quiet back bays of wilderness lakes and untamed rivers. 
- 2010  Some of the questions are for sailboat operators, so aren't relevant for power-boat owners; some are for people in highly congested waterways, so aren't relevant for the guy fishing from a canoe in a back bay of a deserted lake. 
- 2010  On the morning of our second day the waves on the main lake are still high. We decide to venture into a back bay to cast for northern pike. The water is only a couple of feet deep as the guide raises the motor to get us to where he thinks big ones may be lurking. 
- 2014  Often back bays attached to bigger lakes are shallow at the entrance but get relatively deeper when you get into them. These can be fishing hot spots, which receive very little fishing pressure. Some of my biggest fish have been caught in places like these.