Butter an 8x8-inch pan and pour fruit into it. Mix together oats, sugar, flour, cinnamon and cardamom; cut in butter till mixture is crumbly. Pour topping onto fruit. Bake at 375F for 30 minutes, or until fruit bubbles and topping is brown. This is best served warm, with ice cream or whipped cream. Make it up any time during the day, put in the refrigerator, then bake just before serving.
The derivation of these terms is quite easy to see: fresh fruit is layered in a pan and topped with a mixture of sugar, flour, butter, and cinnamon, with thick oat flakes ("old-fashioned" rolled oats) added in some versions. (Some cookbooks even make the distinction: crisps contain oatmeal, crumbles do not.) The dish is baked, causing the fruit to exude its juice and bubble, while the topping becomes brown and crisp. When you bite into this simple, luscious dessert, the crisp topping crumbles - thus "crisp" and "crumble."