Dictionary is a source of words that are neatly arranged
What is function of dictionary in understanding content of reading? Oh, of course there are many functions. Especially if you work as a student or lecturer. Where you have main task of educating students. In process of educating and teaching, of course you cannot be separated from compiling teaching materials to making materials every day.
Material that is made cannot be arbitrary. Must be in accordance with curriculum and follow latest scientific developments. So, in compiling material, you need various references from books, papers, journals, and various other sources.
Not infrequently you look for references to foreign journals which use English or other languages. What is your function in understanding text? Yes, this is where it works.
By using a dictionary, it will be easier for you to understand contents of references sourced from foreign scientific publications. You will be helped to understand one word at a time so you don't get confused yourself.
Function of dictionary in understanding content of reading is same as definition of dictionary itself. A dictionary is a reference book that contains words and expressions, usually arranged in alphabetical order with a description of their meaning, usage and translation.
In contrast to a dictionary, a reference that provides descriptions of various branches of science or certain fields of science in separate articles, it is called an encyclopedia, whereas if the words are not arranged alphabetically but are arranged on basis of grouping hyponyms, synonyms and antonyms, it is called thesaurus.
A useful dictionary helps users to recognize new words and their meanings. In addition to explaining meaning of word, dictionary also contains ways to pronounce word, explains origin of word and provides examples of its use in society.
Do you still use a dictionary in form of a book? Or maybe you have used technology with the translation features provided by search engines on internet?