Merriam-Webster Collegiate Dictionary - parallel

 I. adjective  Etymology: Latin ~us, 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 ~ rows of trees  b. everywhere equally distant concentric spheres are ~  2.  a. having ~ sides a ~ reamer  b. being or relating to an electrical circuit having a number of conductors in ~  c. arranged in ~ a ~ processor  d. relating to or being a connection in a computer system in which the bits of a byte are transmitted over separate channels at the same time a ~ port — compare serial  3.  a.  (1) similar, analogous, or interdependent in tendency or development  (2) exhibiting ~ism in form, function, or development ~ evolution  b. readily compared ; companion  c. having identical syntactical elements in corresponding positions; also being such an element  d.  (1) having the same tonic — used of major and minor keys and scales  (2) keeping the same distance apart in musical pitch  4. performed while keeping one's skis ~ ~ turns  Synonyms: see similar  II. noun  Date: 1551  1.  a. a ~ line, curve, or surface  b. one of the imaginary circles on the surface of the earth ~ing the equator and marking the latitude; also the corresponding line on a globe or map — see latitude illustration  c. a character

used in printing especially as a reference mark  2.  a. something equal or similar in all essential particulars ; counterpart  b. similarity, analogue  3. a comparison to show resemblance  4.  a. the state of being physically ~  b. an arrangement of electrical devices in a circuit in which the same potential difference is applied to two or more resistances with each resistance being on a different branch of the circuit — compare series  c. an arrangement or state that permits several operations or tasks to be performed simultaneously rather than consecutively  III. transitive verb  Date: 1598  1. to indicate analogy of ; compare  2.  a. to show something equal to ; match  b. to correspond to  3. to place so as to be ~ in direction with something  4. to extend, run, or move in a direction ~ to  IV. adverb  Date: circa 1747 in a ~ manner