Synedoche, Metonymy

 

Synedoche

this is when a part is used to represent a whole. E.g The gray hair
are respected in Africa.( grey hair represents or stands for old
people).

Metonymy

this is when something that is closely associated to a particular
thing is used to represent that particular thing. E.g The benches are
here stands for judges and it is closely associated with judges.