Hi Lena, without context, 'throb' can be difficult to explain but I can give you some examples that might help:- 1) 'I've just drank a lot of coffee and now my heart is throbbing'. 'To throb' suggests a quick and strong heart beat/pulse, which may be uncomfortable. 2) 'Harry Styles is a heart throb'. 'Heart throb' suggests a person who is so fanciable that he/she causes their admirer's hearts to beat strongly :) 3) 'I wish that red spot on my face would stop throbbing'. This suggests a painful or uncomfortable pulsating sensation 'Throb' can also be used in the context of music e.g. 'This track has a throbbing bass'. This suggests that the music has a strong regular beat. When comparing 'throb' to pulse or beat, 'throb' is a stronger word.

Can you give some more context please? They can mean different things in different situations. Are you referring to cardiac activity?