Howlers

Comic blunders by schoolchildren have been collected by H. Cecil Hunt and published under the title Henpicked Howlers. Some examples are given here:

An epistle is the wife of an apostle.
Chivalry is the attitude of a man to a strange woman.
Louix XVI was gelatined.
Catarrh is a musical instrument, especially in Spain.
Philosophy means being able to explain why you are happy when you are poor.
When letters are in sloping type, they are in hysterics.
The Tropic of Cancer is a rare and dangerous disease.
An antidote is a funny story you have heard before.
Doctors say that fatal diseases are the worst.
Ali Baba means being somewhere else when the crime was committed.
A symposium is something like a symphony, only not as bad.
Contralto is a low kind of music that is sung only by ladies.

— Herbert V Prochnow & Herbert V Prochnow Jr. in Jokes, Quotes & One Liners Volume 2