I agree, this word needs context. In combination with "my" and without any context, I think "destiny" and "purpose" are probably the best translations. Although several others would make sense, too, if put into context (e.g., "My designation of my successor" = "Meine Bestimmung meines Nachfolgers", compare with Oxford dictionary entry for "designation").
I'm a native German speaker and quite good at English, but maybe the subtle nuances of the numerous possible English translations for "Bestimmung" escape my knowledge. If in doubt, check dict.leo.org (http://dict.leo.org/ende/index_de.html#/search=bestimmung). There are currently 19 translations for "Bestimmung" and you can always ask in the forum.
Anyway, I'm not sure whether "Bestimmung" should be one of the most important words to learn withing business context, so don't worry about it too much.
Not too sure if this is going to help you, coming as it after more than a month. But here's what I found in another thread. The answer was provided by sakasiru:
Schicksal is what is happening to you and you don't have any influence on it; it is most often used for something negative (like a terminal illness). It also has always already happened to you when you notice it. Bestimmung means someone is convinced that you are meant to do/to be something (like become the next king), and that someone can very well be you. So you can actually choose to have one, like deciding it is your Bestimmung to live in a convent. You usually have to follow it (or you want to follow it if it's your idea in the first place), but unlike Schicksal, you can also try to avoid it.
'Bestimmung' has many different meanings. If you say 'meine Bestimmung', it clearly means 'my destiny'. 'destination' isn't really a meaning of 'Bestimmung'. Do you mean 'determination'? (as in the case of classifying an animal or plant species). EDIT: "Bestimmungsort" means "destination (of a letter or parcel).