heartstring

English

Etymology

From heart +‎ string.

Noun

heartstring (plural heartstrings)

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