What exactly means ولي عحد ?
I were reading an article in Al Jazeera today that reported something about the Crown Prince of Saudi Arabia. Or so it seemed, because GoogleTranslator gave me "Crown Prince" for ولي عحد (walia eahd).
Actually, in portuguese it was "Heir Prince". But if I look for the arabic of heir, it is وريث (warith) and prince is أمير (amir). Not even crown is there: تاج (taj).
So, it seems that ولي عحد is an expression for Crown Prince, but with other words.
Now I search again, and found that the translation, to english, of ولي is guardian, or custodian. But for عحد I couldn't find anything meaningfull.

Question

What exactly means ولي عحد ?
I were reading an article in Al Jazeera today that reported something about the Crown Prince of Saudi Arabia. Or so it seemed, because GoogleTranslator gave me "Crown Prince" for ولي عحد (walia eahd). 
Actually, in portuguese it was "Heir Prince". But if I look for the arabic of heir, it is وريث (warith) and prince is أمير (amir). Not even crown is there: تاج (taj).
So, it seems that ولي عحد is an expression for Crown Prince, but with other words. 
Now I search again, and found that the translation, to english, of ولي is guardian, or custodian. But for عحد I couldn't find anything meaningfull.

Answer

No, compromised doesn't mean عهد . but, covenant does

Answer

ولي العهد = crown prince
and there is a mistake you wrote عحد  which is wrong its (عهد )
crown prince (in some countries) a male heir to a throne. according to the google translate ..

Answer

ولي العهد = crown prince

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