мишница

From миш (miš, “mouse”) (dated) +‎ -ница (-nica). For the semantic shift, compare Latin mūsculus (“muscle”) (originally little mouse).

• IPA^(key): [ˈmiʃnit͡sɐ]

ми́шница • (míšnica) f

1. biceps

   Synonym: би́цепс (bíceps)

2. (by extension) upper arm (from the elbow to the shoulder)

   Synonym: рамени́ца (rameníca)

• подми́шница (podmíšnica, “armpit”)

• ми́шца (míšca, “muscle”) (dialectal)

• “мишница”, in Речник на българския език [Dictionary of the Bulgarian Language] (in Bulgarian), Sofia: Bulgarian Academy of Sciences, 2014
• “мишница”, in Речник на българския език [Dictionary of the Bulgarian Language] (in Bulgarian), Chitanka, 2010