Definition
An algebraic expression made up of three terms connected by plus or minus signs, such as a + b − c or 2x² + 3x − 5.
Plain English
A math expression with exactly three parts joined by plus or minus signs.
Context Anchor
Seen in aircraft identification, military aircraft references, maintenance records, and performance or equipment discussions where the exact aircraft version matters.
Derivation
From Latin tri- meaning 'three' and the Greek-rooted -nomial meaning 'name' or 'term.' So a trinomial is literally a 'three-term' expression — which is exactly what it is.
Why Pilots Care
The exact aircraft version can affect equipment, limits, procedures, and performance. Reading the full trinomial helps prevent treating one version of an aircraft as if it were another.
Intuition Check
Do not read trinomial only as a math word. In aviation, it means a three-part aircraft designation, not a math expression.
Example Sentence 1
The performance formula was a trinomial with three terms the technician had to evaluate in order.
Example Sentence 2
Maintenance training included factoring a trinomial to solve for unknown values in a fuel-flow calculation.