To adorn something is to decorate it — to put something pretty or special on it so it looks finer. You adorn a room with flowers, a hall with lights, a person with jewellery. The past form adorned with is very common: the table was adorned with fruit. It is a somewhat dressy, bookish verb. Though actually, most people in ordinary life say decorate, dress, or put up. You are more likely to meet adorn in invitations, stories, and careful writing than in “Can you adorn the classroom?” There is a related noun adornment for the thing you add, but the everyday job of this word is the verb.