The Sauna Lexicon
The Finns have an extensive sauna related vocabulary that is difficult or even impossible to translate.
sau'na: (or sow'-) n. (Building for) Finnish-style steam-bath. [Finn] - The Concise Oxford Dictionary. The correct pronounciation for sauna is sow-na (as in "cow"), not saw-na.
Also saunoa, action of bathing in a sauna and saunoja, a person bathing in a sauna.
The heater of the sauna. Heated with wood or electricity, it has stones on top for increased heat capacity. The more there are stones, the better is the heat the stove gives. A wood heated stove is often thought to give a more pleasant warmth.
Lauteet (singular laude) are wooden platforms in the sauna for people to sit on. They are placed relatively high in the room, so the bathers can enjoy the hotter air close to the roof.
Löyly: steam or vapour
To make the humidity rise in the sauna, one throws water on the stones of the stove. Löyly is the resulting steam. Also heittää löylyä, the action of throwing water.
The steam is hot (nearly 100 degrees Celsius) and causes the room temperature to go up temporarily. Since water carries heat much more efficiently than air, you will feel the change instantly. The steam is hottest near the roof and bathers sometimes react by bending down to avoid it. (Lots of Ooohs and Aaaahs may be heard as well....)
Vihta or vasta
A thick bunch of birch twigs, approx. 40 cm in lenght. Used to slap on oneself to promote blood circulation and cleanse the skin. Also vihtoa, the action of slapping.
The vihta is not used as a whip, although it may so seem to the inexperienced sauna-goer. It is not supposed to hurt, but to make the skin tingle for a while. In the United States, where birch is not as common as in Finland, some people have started using cedar with good results. In Israel, where birches are hard to come by, Pinhas Baraq uses "tsaftsafa" or poplar.
The vihta is made in the summer, just before the Midsummer's Feast, by cutting birch twigs that have a lot of leaves and tying them together. It should be a thick bunch of young, tender branches. It is important for it to have many leaves, as they make the slapping softer and more pleasant.