Fixed expression

[Danial2005]

Hi
I am wondering what dose "in fixed expression "mean in the context:He turned to his son and,in a different tone and fixed expression,said...

many thanks!

[Jamie (K)]

"Fixed expression" has two meanings.

In the one you want here, fixed expression means a firm, focused expression on the face. Sometimes when someone is concentrating very hard on a task, he or she will have a fixed expression. You can also have a fixed expression on your face when you are angry at someone and are staring very firmly into his eyes.

A "fixed expression" can also mean a group of words that people use in a language without changing them. It is a type of idiom that can't have any variation.

[Danial2005]

Hi Jamie (K)
Thank you for your explaination
It is very helpful!

Best regards

Danial