Loudly.
Loud. Used as a dynamic directive in sheet music in its abbreviated form, "f.", to indicate raising the volume of the music. (Abbreviated in musical notation with an f, the Unicode character 1D191.)
A strength or talent.
A passage in music to be played loudly; a loud section of music.
The strong part of a sword blade, close to the hilt.
The one weakness of something or someone that is otherwise invulnerable, an Achilles heel.