What does "first-order" mean?

Of one of a series of models, languages, relationship, forms of logical discourse, etc., being the simplest one or the first in a sequence.

First-order

adj

adj ·Rare ·Advanced level

Adjective

1
Of one of a series of models, languages, relationship, forms of logical discourse, etc., being the simplest one or the first in a sequence. not-comparable
2
Of fundamental importance. not-comparable
"If our goal is to put out the fire—to alleviate a humanitarian crisis broadly referenced in mainstream discourse as "mass incarceration" and "overcriminalization"— that are the specific benefits that flow from making fair policymaking process a first-order principle in the criminal-justice reform movement?"

"Tom is a language genius who speaks 10 languages fluently, but he's really bad at maths and can't even solve a simple first-order equation."

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.