f., pl. mýss, acc. mýs, mod. mýs; [A. S. mûs, pl. mýs; Engl. mouse, pl. mice; O. H. G. mûs; Germ. maus, pl. mäuser; Dan. muus; Lat. mus; Gr. μυς]:—a mouse, H. E. i. 482, Al. 169, Stj. 23; spilltu mýss kornum ok ökrum, var þar víða jörð hol ok full af músum, Bs. i. 293; mús hljóp áðan á kinn mér, Fs. 140; sér köttrinn músina? Ísl. ii. 309; svá hræddr sem mús í skreppu, Fms. vii. 21; hlaupa hingat ok þangat sem mýss í holur, viii. 39; veiða mýs, to catch mice; mýss svá stórar sem kettir, Ó. H. 109 (rats?); þá sá hann mýs tvær aðra hvíta en aðra svarta, Barl. 56; mýss Valkar, Welsh mice, strange mice = rats, Fms. xi. 279; whence mod. Icel. valska, q. v.; flæðar-mús, skógar-mús, a wood-mouse, mus sylvaticus, Eggert Itin.: allit., maðr og mús, thus in Danish if a ship is lost, ‘med mand og muus,’ i. e. with all hands. In tales mice are said to pass over rivers on cakes of cow-dung (skán), steering with their tails, see Eggert Itin. ch. 329, and Ísl. Þjóðs., which reminds one of the witch who sails ‘like a rat without a tail’ in Shakespeare’s Macbeth. For the fabulous tales of wizards keeping a flæðar-mús that it may always provide them with money see Maurer’s Volks.; when the wizard dies, the mouse breaks loose into the sea and a tempest arises, called Músar-bylr, mouse-tempest; that a similar superstition existed in olden times may be inferred from the name Músa-Bölverkr, Landn.

2. the name of a mouse-gray young cow, Ísl. ii. 401.

COMPDS: músarbragð, músarbróðir, músarrindill, músareyra, músagangr, músagildra.

B. Metaph. the biceps muscle in the arm; þá flaug ör ein ok kom í hönd Hákoni konungi upp í músina fyrir neðan öxl, Hkr. i. 159; kom ein ör í handlegginn í músina, Bs. i. 781: mûs in A. S. and O. H. G. is used in a similar sense; cp. also Lat. musculus = a little mouse, whence muscle: the chief muscles of the body were named from lively animals, thus fiskr of the cheek (kinn-fiskr), mús of the arm, kálfi (calf) of the leg.