Literally translated, the Greek word phyllo means "leaf. " Culinarily, it refers to tissue-thin layers of pastry dough used in various Greek and Near Eastern sweet and savory preparations, the best known being baklava and spanakopita. Phyllo (also spelled filo) is very similar to strudel dough. Packaged fresh and frozen phyllo dough is readily available — the former in Greek markets, the latter in supermarkets. Unopened, phyllo can be stored in the refrigerator for up to a month. Once opened, use within 2 to 3 days. Frozen phyllo can be stored for up to 1 year. Thaw overnight in the refrigerator. Refreezing phyllo will make it brittle.