Fika is a Swedish verb that roughly means "to take a coffee break".
Fika is a social institution in Sweden: it means taking a break from work or other activities and having a coffee with one's colleagues, friends, or family. This practice of taking a break for a coffee and a light snack (some biscuits, cookies, or a sandwich) between more substantial meals like lunch and dinner is central to Swedish life, Swedes being among the heaviest consumers of coffee in the world.
Since the word implies drinking coffee, just having a sandwich would not really be fika, although these days tea instead of coffee is becoming more frequent. In recent years, too, fika has also come to mean simply going to a café and having a coffee with someone, though this technically deviates from the strict "taking a break" meaning.