"::'Perceber' is actually very common in Brazil, but here it means ""to notice"", ""to realise"" or ""to perceive"". (I didn't even know it could mean 'entender' until I came to Wikipedia.) 'Compreender' is usually the same thing as 'entender', but sounds more formal. It means ""to understand"" or ""to contain"", just as in English.   

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