Championship vs Competiton

the dictionary I’ve looked into can’t tell me any differences between these two words:
Championship VS Competiton

could someone help please ?

A “competition” is any kind of contest or sports match.

A “championship” is a contest or sports match to see who is number-one in the state, nation or world.

There are soccer and baseball competitions in my town all the time, but neither one is meant to tell who is the champion. They just determine who won that day. Some of them are just for practice. However, the World Cup games are championships to see who is the best soccer team in the world, and the World Series is a championship to see who is the best baseball team in English-speaking North America.

Thank you so much for the help, Jamie!
BTW, sometimes I can see there are some single capital letters embraced by
a pair of square brackets next to the definition of a word, for example:
when I checked for the meaning of the word Solitary in my dictionary,
I see these lines:

solitary [A][Z], person, animal or object is one which is not in the companionship of others of its type. "He formed the habit of taking long solitary walks through the streets."
What do [A] and [Z] stand for respectively?

I don’t think those are standard English dictionary notations, and I don’t understand them. You need to look at the list of abbreviations at the beginning of your dictionary to find out what they mean. Which dictionary are you using?