triquaternion

from The Century Dictionary.

• noun In mathematics, an expression of the form q₁ + ωq₂ + μq₃, where q₁, q₂, q₃ are quatornions, and where the symbols ω and μ are commutative with quaternions, and where ω = 0, and μ = 1, and μω = − ωμ = ω.