We use a dictionary for two main reasons--to find out how to spell a word, and to find out the meaning of a word.
All the words in a dictionary are in alphabetical order. This means words that begin with the letter a are at the beginning of the dictionary. Words that begin with the letter z are at the end of the dictionary.
The second letter of a word is also important. For example, the word act comes before the word is also important. For example, the word act comes before the word ant. This is because the letter c comes before the letter n in the alphabet. For the same reason the word bag comes before the word bar.
People who do not know the alphabet cannot use a dictionary. They do not know how to find words.
One of the most famous dictionaries in the world is the Oxford English Dictionary. It gives the meaning and spelling of all words in the English language. Most dicitionaries do not have every word.