Tomatsås is ‘tomato sauce’. Tomat, lycopersicon esculentum, comes via Spanish tomate from nahuatl (the Aztec language) tomatl. Lycopersicon comes from Greek lykos – ‘wolf’, and persikon – ‘peach’, orignally that must have been another fruit than tomato, probably a bitter one. Esculentum is ‘edible’, from Latin esca – ‘food’.
Sås is ‘sauce’, coming via French sauce from Latin salsa ‘salty stock’, from sal, salis, ‘salt’.
I make tomato sauce preserves each autumn, mixing the tomatoes with some pieces of squash, carrots, celeriac, onions and garlic.