Union Jack
The California flag is called the bear flag.
Commonly known as Ulster Flag actually the Ulster Banner. However as NI is part of the UK the Union Flag would be the correct flag politically. The Diagonal red cross in the Union Flag represents Ireland
It is called "Red Ensign". The Ontario's flag is called "Red Ensign".
A flag specialist is called a vexillologist.
A knight's flag is called a Pennon. It is a small flag on end of lance.
The "field." The horizontal length of the flag is called the "fly." The height of the flag is called the "hoist."
A Flag
Such a flag is called a national flag.
This is the flag of Iglesia ni Christo here in Republic of Philippines. I believe it is used elsewhere as well.
a flag maker is called a bing bong beggar
pennant or pennon
When you hit the flag in golf its called a pinshot.