Throb and Thrum

Throb verb - To expand and contract in a rhythmic manner.

Thrum is a synonym for throb in pulsation topic. In some cases you can use "Thrum" instead the word "Throb" as a verb or a noun, when it comes to topics like pulsate.

Thrum verb - Sound the strings of (a string instrument).

Throb is a synonym for thrum in beat topic. You can use "Throb" instead the word "Thrum" as a verb or a noun, if it concerns topics such as buzz, quiver.