Pölsa is a traditional Swedish dish, very similar in taste and consistency to Scottish haggis

Haggis

Haggis is a dish containing sheep's 'pluck' , minced with onion, oatmeal, suet, spices, and salt, mixed with stock, and traditionally simmered in the animal's stomach for approximately three hours. Most modern commercial haggis is prepared in a casing rather than an actual stomach.Haggis is a kind...

. The main ingredients are liver

Liver

The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

, heart

Heart

The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

, onion

Onion

The onion , also known as the bulb onion, common onion and garden onion, is the most widely cultivated species of the genus Allium. The genus Allium also contains a number of other species variously referred to as onions and cultivated for food, such as the Japanese bunching onion The onion...

, pot barley, and often beef mince or minced pork, mixed with stock, black pepper, and marjoram

Marjoram

Marjoram is a somewhat cold-sensitive perennial herb or undershrub with sweet pine and citrus flavours...

. It is usually served with boiled or fried potatoes, pickled beetroot, and sometimes a fried egg.

The dish plays a central role in Torgny Lindgren

Torgny Lindgren

Gustav Torgny Lindgren is a Swedish writer.Lindgren is the son of Andreas Lindgren and Helga Björk. He studied in Umeå to become a teacher and worked as a teacher until the middle of the 1970s. He was for several years active as a local politician for the Swedish Social Democratic Party...

's allegorical novel Hash (Pölsan), in which two men go on a personal quest across postwar Sweden in search of the genuine Swedish "pölsa".

The Norwegian and Danish word, pølse

Pølser

Rød Pølse is a type of boiled sausage very common in Denmark and Norway. Since hot dog stands are ubiquitous in Denmark some people regard røde pølser as one of the national dishes. Their most noticeable aspect is that the skin often contains a traditional red dye making it bright red...

, means sausage and even if the two dishes don't look the same, the two words are related. Pölsa is simply a traditional variety of sausage filling without any casing.
The word pølse

Pølser

Rød Pølse is a type of boiled sausage very common in Denmark and Norway. Since hot dog stands are ubiquitous in Denmark some people regard røde pølser as one of the national dishes. Their most noticeable aspect is that the skin often contains a traditional red dye making it bright red...

can also describe the appearance of an object, like "it looks like a pølse", and "it's pølse shaped" (i.e. sausage shaped).