EVEN

The word “even” is most commonly used as an adverb even though it may assume the role of at least three other parts of speech: noun, adjective, subordinating conjunction. For example, in the preceding sentence, it is serving in combination with “though” as a subordinating conjunction,  which, by definition, introduces the dependent clause that follows. Writers sometimes wonder whether a preceding comma is required in such situations.
 
The general rule regarding commas with subordinating conjunctions applies here for “even though” and similar combinations, i.e., apart from a couple special cases, a comma is only required when the dependent clause is shifted to the beginning of the sentence.

While most other uses of “even” do not call for a comma, this punctuation is also required when “even” introduces an interrupting phrase that can be removed without altering the meaning of the sentence or is there only to emphasize the surprising nature of something. 

Another notable situation where a comma is mandatory occurs when “even” introduces a participial phrase at the end of a sentence; a participial phrase that ends a sentence is always preceded by a comma.


We think of “even” as “balanced” or “flat”
Or meaning “exactly,” “fully,” or “just”;
Of variation claiming slight;
Surprising states yet emphasized.

As adjective, adverb, noun or verb,
It ranges broadly, role and site;
A speedy tour in orbit grand
Leaves little pause for comma's plight.

But interrupting phrases all,
Participial ones at endings, too,
Are comma's friend when “even”-strung
Like clause dependent firstly grew.

“Thus, even though it's moonlit bright, 
The forest trail seems grave tonight.”
“The bus today was later, even
Forcing them to bum a ride.”

“And once arrived there, even late, 
They walked with pride and smirking smiles.”
Thus illustrated, queue reversed,
Are three of “even” for the files.

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