GM全名係Game Manager定係General Manager?

同意樓上網友的註釋, 在管理學的範疇上, GM是General Manager的縮寫。
在近代的管理學而言, GM的工作是包括下列五個重點:
1.) An obsession with responsiveness to customers;
2.) Constant innovation in all areas of the firm;
3.) Partnership - the wholesale participation of and gain sharing with all people connected with the organisation;
4.) Leadership that loves change and instils and shares an inspiring vision;
5.) Control by means of simple support systems aimed at measuring the "right stuff" for today's environment.
希望以上的資料, 可以幫到你。

The meaning of abbreviations is not fixed. Different parties use different abbreviation for different meaning.

As for GM, it usually refers to General Manager. (Most likely, there will be a
General Manager in a company.)

GM usually directs the company and oversees the daily operations. In some small company, GM is like the CEO (reports only to the boss). In other firms, there could be a few GM's in a regional office alone, and their duties will be more focus on one specific area.

normally refer to General Manager

job duties include smoothening office operation, just kind of administrative support, but in management level