In English, there are many words that have more that one meaning. For instance; the word 'play' could be when actors on stage are acting out a scene, or it could mean that a child is having fun with a game. The word 'star' could be talking about a heavenly body that we see in the night sky, or it could mean a famous actor in Hollywood.
The word 'world' in scripture could have any one of three meanings. It could mean the earthly body that we live on, or it could mean the sinful ways of people, or it could be the people themselves.
As in English, some Greek and Hebrew words have multiple meanings. We might find two different verses that use the same word, but that word may have entirely different meanings in each verse. This is another reason why we must pay attention to the context.