Why are parallelograms defined as quadrilaterals? What term would encompass polygons with greater than two parallel pairs? It seems the definition of a parallelogram is locked to quadrilaterals for some reason. Is there a reason for this? Why couldn't a parallelogram (given the way the word seems rather than as a mathematical/geometric construct) contain greater than two pairs of parallel sides? In a hexagon for example, all six sides are parallel to their opposing side. Is there a term for this kind of object?
It seems to me there must be some value in describing a polygon with even numbers of sides in which the opposing sides are parallel to each other. While a hexagon, octagon, decagon, etc. all match this rule, you could have polygons with unequal sides as well.

Edit 1: Object described by Mark Fischler

Zonogon:


I'm going to propose, out of the blue, terms like "hexaparallelogram", "octaparallelogram", and so forth.
I'm wondering whether, for more than $4$ sides, you would like your definition of hexaparallelogram to be restricted to having 3 pairs of parallel and pairwise equal sides (as in your picture - evidently these have a name, zonogon), or would you include a hexagon with vertices at $\{(0,0), (12,0), (16,6), (4,12), (0,12), (-6,3)\}$ which has three pairs of parallel sides but no two sides of equal length?
Euclid, in proposition 34, introduces the term (παραλληλόγραμμα χωρία) which we can translate to "parallelogrammic area."  So much for the etymology sites that trace the word only to Middle French.  Euclid himself restricted the word to just four-sided figures. Proclus credits Euclid with having introduced the term "parallelogram," as opposed to bringing down that term from earlier works. So that tells us who to blame.
