Etymology: ‘Κόσμημα’ = jewel derives from the Ancient Greek verb (κοσμώ)
‘kosmo’, which means to embellish/ornament something.

Definition of word
Jewel – ornament 
To decorate, add ornaments or appropriate elements so that an object/item or a place becomes more appealing.
To dress somebody in his nicest and fanciest clothes, add jewellery aiming to present the best possible appearance.
To embellish, to beautify my speech or a text with sophisticated words or phaces.