All the words in a language make up what is generally known as its vocabulary. The term“vocabulary”is used in different senses. Vocabulary is most commonly used to refer to the sum total of all the words of a language. It can also refer to all the words of a given dialect,a book,a subject,and all the words possessed by an individual person as well as all the words current in a particular period of time in history. English is one of the world's highly developed languages. Naturally,the vocabulary is one of the largest and richest. The general estimate of the vocabulary is over one million words.