Meaning of the word lub in English

What does lub mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

lub

US /lʌb/
UK /lʌb/

Noun

the sound made by a heartbeat, especially the first, duller sound

Example:
The doctor listened to the distinct lub-dub of her heart.
Each strong lub of his heart echoed in his ears.