KenJuma

I'm new to php and my first assignment is to design a project that give a user synonyms to words and also allows the user to add words and their synonyms. The thesaurus doesnt have to be full of all the words, an example of two or three words would just be enough. I do not want to use a database since I want to fullu understand php before starting to interact with databases. Someone told me I could save the words in some file which will be accessed by the codes and when the user enters the new words, they would automatically be updated in the file. I was thinking of using arrays, any help..?