parallelogrammic

from The Collaborative International Dictionary of English v.0.48

Parallelogrammic \Par`al*lel`o*gram"mic\
   (p[a^]r`al*l[e^]l`[-o]*gr[a^]m"m[i^]k), Parallelogrammical
\Par`al*lel`o*gram"mic*al\
   (p[a^]r`al*l[e^]l`[-o]*gr[a^]m"m[i^]*kal), a.
   Having the properties of a parallelogram. [R.]
   [1913 Webster]