It's singular. "First honors" is also equivalent to "all the honors of being first", or "first over all honors". So, yeah, singular. But I bet it's safer to use First Honor instead, without the s.
The abbreviation of "have not" is "haven't."
The abbreviation of electron is e−.
There would be no abbreviation for Houston, but the abbreviation for Texas is TX.
There is no abbreviation.
"With" in latin, is cum, as in magna cum laude: "with" highest honors. That's why a C with a line over it, denotes the latin translation.
Passing honors, side honors, gun salutes
He received many honors in high school. She honors her parents. She received three honors in her lifetime.
Graduate with honors.
The Honors tab is a signal to Honors Credit students that they have an Honors assignment to complete.
She received honors for her outstanding academic achievements.
Honors
1st honors
It is possible to use honors in a sentence. Here are a few examples. Sally graduated high school with honors. Albert enjoyed the honors banquet.
no that is illegal
the White House honors the president.
In the US there is no month that honors firefighters I am aware of.