Before students can engage in fun dictionary activities, they'll have to learn how to use the dictionary. Show your students how to put words in alphabetical order, then explain that the entire dictionary is in alphabetical order. Have them test out their new skills by giving them a list of words to find and circle in their dictionary.
Hold up a word that's most likely not familiar to all of your first graders. Ask the students what they think the word means. Try to have the class come up with two or three definitions for the word and write them on the board. Then have your class look the word up in their dictionary and read the actual definition or definitions out loud. Not only will they get a good laugh at what they thought the word meant in comparison to its actual meaning, but they'll also learn that some words have more than one definition while expanding their vocabulary.
Write several different words on small pieces of paper, fold the paper and place all the pieces into a large bowl or hat. Have each child pick one piece of paper and read their word privately. Assign them the task of looking up the word in the dictionary, writing down each definition for the word and then constructing a sentence using each meaning of the word. This will help your students learn how to use certain words and also remember new words.
By turning a simple task of looking up words in the dictionary into a fun, competitive treasure hunt, your students will have more enthusiasm for the task. Give everyone a list of the class' vocabulary words and see which student can find all of the words the fastest. To make this task more fun and challenging, write clues to what the word is. Your students will have to first figure out what word you want them to look up and then they'll actually have to find the word in the dictionary. If they're all using the same dictionary, have them jot down the page number next to the clue or word for which they're searching.