Sometimes unknown words appear while we are reading a text, the easiest way to determine it's meaning is by using a dictionary. A dictionary will tell you the different meanings of a word, how it is pronounced and the correct way to use it. However, sometimes we don't have a dictionary available, in that case the best way to determine the unknown word's meaning is by using the context. The surroundings of the words may give you a clue, by reading the whole sentence or paragraph you can be able to figure it out. Maybe the word you don't understand is described in another way in the paragraph or maybe it is used in an example that might help you.
