n. — predominantly Prairies, (children's) hockey, historical
a piece of frozen horse manure used as a hockey puck.
Type: 5. Frequency — In Canada, road apple appears to have undergone semantic change from the more general meaning of "horse manure" (see DARE, s.v. "road apple"). The term is virtually restricted to Canada (see Chart 1), with cultural significance because of its connection to the Canadian love of hockey.
See also COD-2, s.v. "road apple" (2), which is marked "Cdn hist", and DARE, s.v. "road apple".
See also: hockey puck shinny (meaning 1a)
- 1961  As a former Winnipeger, I recall playing hockey with a frigid road-apple on the Assiniboine River Rink, at the foot of Kennedy Street, when it was 35-below. A few sissies wore mitts. It was so cold in those days that two cousins of mine (they were barefoot boys from out-of-town) were frozen in mid-flight across Portage Avenue at least once each winter. 
- 1982  AL STRACHAN NO SPORT is as much a part of the true Canadian life style as hockey.
Some of the stars of earlier generations grew up playing the game on busy streets using rock-hard road apples as a puck. Others played it on the frozen ponds of the prairies with liberated catalogues as pads. 
- 1989  Everyone who knows the difference between a hockey puck and a road apple figured the Canucks would be swept aside in four games, maybe five. Tom Watt, the cocksure assistant coach of the Flames, was so confident that he actually hoped the Canucks might win a game so the Flames wouldn't get fat and rusty waiting for the next round. 
- 1993  There was fun, however, in the midst of the disruptions. There were chocolate bars and horse operas for 16 cents at the Rose Theatre, street hockey with frozen road apples, saxophone playing with the Edmonton Newsboys' Band, and endless practical jokes. Jack delighted in recalling for his grandchildren the Halloween escapades, the stink bomb and itching-powder pranks that got him kicked out of the church choir for all time. 
- 2012  When times were hard, during the Great Depression for example, shinny players used whatever makeshift equipment they could get their hands on, including tree branches and broom handles for sticks and a tin can or a frozen road apple for a puck.
Hockey became more organized over time, but shinny remains delightfully fluid. 
Images:
Chart 1: Internet Domain Search, 15 Jan. 2014