The quality or state of being preeminent; superiority in prominence or in excellence; distinction above others in quality, rank, etc.; rarely, ...

'preeminence' -- उत्कर्ष /अग्रता/सर्वश्रेष्ठ/ सर्वोत्तम

It can also be translated as सर्वोत्तम नीति

no need.

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Note added at 1 hr (2008-03-13 12:41:33 GMT)
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Superior to or notable above all others. According to http://www.entrepreneurs-journey.com/773/how-to-launch-a-mem... is essentially a perception. It simply means that people believe you are the best or one of the best or at least better than most others, at what you do. It’s because of preeminence that people choose your business over the competition. Example sentence in Hindi can be written as follows-
भारतीय इस्पात प्राधिकरण लिमिटेड (सेल) को वर्ष 2006-07 के स्कोप उत्कृष्टता पुरस्कार के लिये चुना गया है

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Note added at 1 hr (2008-03-13 12:44:28 GMT)
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किसी भी कंपनी को अपनी साख बनाए रखने के लिए उत्कृष्टता की नीति का अनुसरण करना होता है।

preeminence is a vague term in English with a large number of synonymns, which is why different answeres have suggested different terms which are all more or less correct. Here is one more.

If possible check with your client to find out what he/she actually means by this term. That will help you to pin it to a more definite meaning. After that a suitable Hindi term can be selected.