Heartstring

Noun

1. singular of heartstrings A tendon or other structure resembling a cord once thought to be attached to, or to brace, the heart. A source of one's deepest emotions or inner feelings, especially compassion or love. The essential or vital part of something; the core, the essence, the heart.
2. A tendon or other structure resembling a cord once thought to be attached to, or to brace, the heart.
3. A source of one's deepest emotions or inner feelings, especially compassion or love.
4. The essential or vital part of something; the core, the essence, the heart.