Main Entry: 1par·al·lel
Pronunciation: 'par-&-"lel, -l&l
Function: adjective
Etymology: Latin parallelus, from Greek parallElos, from para beside +
allElOn of one another, from allos... allos one... another, from allos
other -- more at ELSE
Date: 1549
1 a : extending in the same direction, everywhere equidistant, and not
meeting parallel rows of trees

Now what part parallel doesn't a planer do?

"Edwin Pawlowski" wrote in message
news

Using a planer only, it is possible to get both faces flat, but
not parallel to each other.