noun

• The state or condition of being parallel; agreement in direction, tendency, or character.
• The state of being in agreement or similarity; resemblance, correspondence, analogy.
• A parallel position; the relation of parallels.
• (rhetoric, grammar) The juxtaposition of two or more identical or equivalent syntactic constructions, especially those expressing the same sentiment with slight modifications, introduced for rhetorical effect.
• (philosophy) The doctrine that matter and mind do not causally interact but that physiological events in the brain or body nonetheless occur simultaneously with matching events in the mind.
• (law) In antitrust law, the practice of competitors of raising prices by roughly the same amount at roughly the same time, without engaging in a formal agreement to do so.
• (biology) Similarity of features between two species resulting from their having taken similar evolutionary paths following their initial divergence from a common ancestor.
• (computing) The use of parallel methods in hardware or software, so that several tasks can be performed at the same time.