If you study Japanese or study in Japan, you may have some occasions to use a Japanese dictionary. A Japanese dictionary explains Japanese words in the order of the Japanese alphabet. You can find the meaning, the Japanese grammar, the accent, the Chinese character and the example of the word which you refer to a dictionary.
There are many types of dictionaries and one dictionary has words from 50,000 to 500,000. The oldest dictionary in existence was written by a famous priest in the 9th century. Computerized dictionaries and internet dictionaries are popular, nowadays.
By the way, I like “Fune wo amu (Knitting a ship)”, a movie describing editors who make a Japanese dictionary. It shows how it takes much time with huge difficulties to make a Japanese dictionary. As time goes by, many new words are invented or imported while some words are forgotten. Especially, Japanese always have preferred new words from overseas since long time ago. Thus, editors of a dictionary don’t have to lose their jobs, forever.