What French word describes a small, tender filet of beef?

What word names a small cave, like the famous "blue one" on Capri? A small chapel in a village northwest of Moscow marks the source of which river, more than 2,000 miles long? What is a small cucumber preserved in vinegar or brine called? A small, dim star such as Proxima Centauri is called what? What is a small folded pastry with a sealed edge called? What name belongs to both a Hawaiian hawk and a moon of Jupiter? What is a small hole or wound made by a sharp object called? What is a small, lightly armed patrol boat called?