I'm normally use to the word "optional" but there is also the word "facultative" ( https://www.merriam-webster.com/dictionary/facultative ) which also seems to mean "optional".

I encountered "facultative" when one of my French co-workers wrote an English text. Initially I thought it's wrong and just a false friend, but then I was able to look it up and confirm that "facultative" can mean "optional"

So my question is

Are there subtle differences?
When should one use one, when the other?

In computer science would both of the following be correct:
"facultative function argument" / "optional function argument"?

Addendum: I am new to English Language and Usage. The question has been closed, but I don't fully understand why.

Though it is common stackexchange practice to close questions without trying to help the OP to improve the way they should post questions, I personally think the quality of stackexchange would improve faster if users would comment instead of throwing out canned responses.

The standard response is:

Please include the research you’ve done, or consider if your question suits our English Language Learners site better. Questions that can be answered using commonly-available references are off-topic.

Should I move it to "English Language Learners" ?

I did not find the commonly-available reference that tells me, that the word facultative is very rarely used and should thus be avoided.

I have no problems, that my question is closed, as I got the satisfying answer, but I would like to understand why this question has no value to others and should therefore be closed.

I changed title and rephrased. Is the question now up to the standards? If not, please explain, such that I can learn.

I'm normally use to the word "optional" but there is also the word "facultative" ( https://www.merriam-webster.com/dictionary/facultative ) which also seems to mean "optional".

I encountered "facultative" when one of my French co-workers wrote an English text. Initially I thought it's wrong and just a false friend, but then I was able to look it up and confirm that "facultative" can mean "optional"

So my question is

Are there subtle differences?
When should one use one, when the other?

In computer science would both of the following be correct:
"facultative function argument" / "optional function argument"?

I'm mostly used to the word "optional" but there is also the word "facultative" ( https://www.merriam-webster.com/dictionary/facultative ) which also seems to mean "optional".

Are there subtle differences?
When should one use one, when the other?

In computer science would both of the following be correct:
"facultative function argument" / "optional function argument"?

Addendum: I am new to English Language and Usage. The question has been closed, but I don't fully understand why.

Though it is common stackexchange practice to close questions without trying to help the OP to improve the way they should psot questions, I personally think the quality of stackexxchange would improve faster if users would comment instead of throwing out canned responses.

The standard response is:

Please include the research you’ve done, or consider if your question suits our English Language Learners site better. Questions that can be answered using commonly-available references are off-topic.

However I did not find the commonly-available reference that tells me, that the word facultative is very rarely used und should thus be avoided.

I have no problems, that my question is closed, as I got the satisfying answer, but I would like to understand why this question has no value to others and should therefore be closed.

I'm normally use to the word "optional" but there is also the word "facultative" ( https://www.merriam-webster.com/dictionary/facultative ) which also seems to mean "optional".

I encountered "facultative" when one of my French co-workers wrote an English text. Initially I thought it's wrong and just a false friend, but then I was able to look it up and confirm that "facultative" can mean "optional"

So my question is

Are there subtle differences?
When should one use one, when the other?

In computer science would both of the following be correct:
"facultative function argument" / "optional function argument"?

Addendum: I am new to English Language and Usage. The question has been closed, but I don't fully understand why.

Though it is common stackexchange practice to close questions without trying to help the OP to improve the way they should post questions, I personally think the quality of stackexchange would improve faster if users would comment instead of throwing out canned responses.

The standard response is:

Please include the research you’ve done, or consider if your question suits our English Language Learners site better. Questions that can be answered using commonly-available references are off-topic.

Should I move it to "English Language Learners" ?

I did not find the commonly-available reference that tells me, that the word facultative is very rarely used and should thus be avoided.

I have no problems, that my question is closed, as I got the satisfying answer, but I would like to understand why this question has no value to others and should therefore be closed.

I changed title and rephrased. Is the question now up to the standards? If not, please explain, such that I can learn.

I'm mostly used to the word "optional" but there is also the word "facultative" which also seems to mean "optional".

Are there subtle differences?
When should one use one, when the other?

In computer science would both of the following be correct:
"facultative function argument" / "optional function argument"?

I'm mostly used to the word "optional" but there is also the word "facultative" ( https://www.merriam-webster.com/dictionary/facultative ) which also seems to mean "optional".

Are there subtle differences?
When should one use one, when the other?

In computer science would both of the following be correct:
"facultative function argument" / "optional function argument"?

Addendum: I am new to English Language and Usage. The question has been closed, but I don't fully understand why.

Though it is common stackexchange practice to close questions without trying to help the OP to improve the way they should psot questions, I personally think the quality of stackexxchange would improve faster if users would comment instead of throwing out canned responses.

The standard response is:

Please include the research you’ve done, or consider if your question suits our English Language Learners site better. Questions that can be answered using commonly-available references are off-topic.

However I did not find the commonly-available reference that tells me, that the word facultative is very rarely used und should thus be avoided.

I have no problems, that my question is closed, as I got the satisfying answer, but I would like to understand why this question has no value to others and should therefore be closed.