Top banana

Top banana means the best in the field, an expert, or it can mean the highest executive or boss in an organisation. It is an Americanism that dates from the mid-20th century, and apparently derives from music hall, burlesque, and vaudeville shows where the top or lead comedian was known as the top banana, and the straight man was the second banana. Quite why a banana was chosen as opposed to any other fruit is not known, except, perhaps, that falling after slipping on a banana skin was also part of burlesque or vaudeville shows.