Commas are not used to mark defining clauses, but in the definition of the word 'cross' I see it before a defining clause:
an upright post of wood with another crossing it near the top, that people in the past were fastened to as a punishment.
Is that comma before the defining clause 'that people in the past ... ' warranted?
The comma is optional. However, if you put it in, the relative pronoun is "which", not "that." The first phrase is a complete definition, the second, additional commentary or information.
- an upright post of wood with another crossing it near the top, which people in the past were fastened to as a punishment.
- an upright post of wood with another crossing it near the top that people in the past were fastened to as a punishment.
Comments
That mean, in my cited definition the defining clause is 'that people in the past were fastened to as a punishment' that cannot have been preceded by a comma.
Could I say a comma is never given before the word 'that'?
In formal American English, that is used in restrictive (defining) clauses, and which is used in nonrestrictive (non-defining) clauses.
In British English, however, 'that' and 'which' can both be used for restrictive clauses, allowing for a bit more flexibility.
But in both the US and the UK, non-restrictive clauses are only written with 'which'. If you want to avoid confusion, use 'that' for restrictive clauses and 'which' for non-restrictive clauses.
No.
One example where a comma is possible before a 'that':
Oh, that a comma is never possible before the word 'that' is not true.
Therefore, in the definition #4 of the word 'cross' as a noun in the following, the comma warrants removal as the that-clause is restrictive/defining: https://www.ldoceonline.com/dictionary/cross
A comma would be allowed had it been a non-restrictive which-clause, but a that-clause is always restrictive.
Thanks, everything adds up now.
Your example, that is the one about putting a comma before the word "that", is a good one.
Now, that is a much better example that/which you gave!
A restrictive clause must then be a subordinate clause, while a non-restrictive clause appears to be a relative clause. If it is so, that means a comma is not needed before a subordinate clause, while it is needed before a relative clause.
There is no getting away from the fact that this much grammar is what one needs to know just to figure out where to properly use a comma!
The wording above is a noun phrase in which the relative that-clause modifies the head of that phrase. The comma is redundant there.
What I have come to understand from this helpful discussion:
Optionally use a comma if you are sure you are giving some additional information about what you are talking about. Do not use comma in between an essential defining description of a noun or its phrase.