For those working in systems analysis and computer programming area (developers) since the golden days of domain of mainframes (big computers), bears in mind the following definition:
1) System is a set of computer programs, in order to meet a certain area and / or business needs, such as:
1.1) Asset Control System
1.2) Accounting System
1.3) Payroll System
1.4) System of Tax Books
1.5) Financial Control System
1.6) Cash Flow System
1.7) System of Accounts Receivable
1.8) System of Accounts Payable
1.9) Among many other
2) Program is a set of instructions (code lines), in order to perform a particular task or function within the system, or even alone, written in some programming language, compiled or not. Normally, a program that operates in isolation is (or was) called utility.
In the mainframe days (pre PC), in Brazil, when the good and old COBOL language was the king, we called as "bacalhau" (or "baca") a temporary utility program, ie a stop-gap program, which solved a problem and then was discarded.
A system is also known by many as an "application", and more recently we started to rather use the term "app", but in practice, an "app" might be considered a more specific system, smaller, if compared to traditional systems mentioned above.
Date of text making up: 23.01.2015.