Solar Power Network Inc. v. ClearFlow Energy (Ont CA, 2018)
In this case the Court of Appeal sets out the definition of interest:
 Solar Power does not challenge the legal test used by the application judge, at para. 20:
1. Interest is the return or consideration or compensation for the use or retention of money that is owed to another person;
2. interest must relate to a principal amount or an obligation to pay money; and,
3. interest must accrue over time: Saskatchewan (Attorney General) v. Canada (Attorney General), 1947 CanLII 32 (SCC), 1947 S.C.R. 394 at para. 47; Ontario (Attorney General) v. Barfried Enterprises Inc., 1963 CanLII 15 (SCC),  S.C.R. 570, 42 D.L.R. (2d) 137 at para. 5.