To set out for display or use; place in an orderly arrangement: arrayed the whole regiment on the parade ground. To dress in finery; adorn. An orderly, often imposing arrangement: an array of royal jewels. An impressively large number, as of persons or objects: an array of heavily armed troops; an array of spare parts. See Synonyms at display. Splendid attire; finery. Mathematics A rectangular arrangement of quantities in rows and columns, as in a matrix. Mathematics Numerical data linearly ordered by magnitude. Computer Science An arrangement of memory elements in one or more planes.