Celery is a very crunchy, succulent vegetable that grows in stalks. You can cook celery, often with more flavorful vegetables, or eat it raw.
Celery is a very mild-flavored vegetable that adds crunch to a salad or a subtle taste to sauteed onions and garlic. Your grandmother might love to serve "ants on a log," or peanut butter in the hollow of a celery stalk, with raisins as the "ants." Depending on your feelings about celery, you might feel slightly less enthusiastic.