Before Western Canada could be opened up to settlement and farming, a survey system was needed.
In 1871, the Dominion Land Survey surveyors needed a reference point to start surveying. A Second Prime Meridian (the first being through Grenwich, England) was drawn North-South through the middle of Manitoba, close to Winnipeg. This line is called the 1st Meridian and legal land descriptions to the west of this line all end with W1 ie West of the First Meridian. The Second Meridian is the Sask-Manitoba border, and the Third is in the middle of Saskatchewan. The Fourth is the Alberta-Sask border so all legal land descriptions in eastern AB end with W4.
The cache you are seeking is very close to the 5th Meridian (note the West co-ordinate of W 114 00.107) which means standing at the cache you are almost standing on top of the 5th Meridan. All co-ordinates to the east of the cache location are W113 and to the West are W114.
A more detailed description of this can be found by Googling Dominion Land Survey.