ETYM Old Eng. arai, arrai, Old Fren. arrai, arrei, arroi, order, arrangement, dress, French arroi.
1. An orderly arrangement.
2. An impressive display.
3. An arrangement of aerials spaced to give desired directional characteristics.
4. Especially fine or decorative clothing; SYN. finery, raiment, regalia.

1. To place or dispose in order, as troops for battle; to marshal.
2. To deck or dress; to adorn with dress; to cloth to envelop; -- applied esp. to dress of a splendid kind.
3. To set in order, as a jury, for the trial of a cause; that is, to call them man by man.

In programming, a list of data values, all of the same type, any element of which can be referenced by an expression consisting of the array name followed by an indexing expression. Arrays are part of the fundamentals of data structures, which, in turn, are a major fundamental of computer programming. See also array element, index1, record1, vector.
In computer programming, a list of values that can all be referred to by a single variable name. Separate values are distinguished by using a subscript with each variable name.
For example, consider this list of highest daily temperatures:
temperature (şC)
day 1 22
day 2 23
day 3 19
day 4 21
This array might be stored with the single variable name “temp”. Separate elements of the array would then be identified with subscripts. So, for example, the array element “temp(1)” would store the value “22”, and the array element “temp(3)” would store the value “19”.
An array may use more than one subscript. For example, consider this list showing the number of pints of milk delivered to four houses:
house 1 house 2 house 3 house 4
day 1 2 2 3 1
day 2 2 1 2 1
day 3 3 2 0 1
day 4 2 1 2 1
day 5 4 1 2 2
day 6 4 5 4 4
If the array were given the variable name “pint”, its elements would be identified with two subscripts: one for the house and one for the day of the week. So, for example, the array element “pints(2, 6)” would store the value “5”, and the array element “pints(3, 3)” would store the value “0”.
Arrays are useful because they allow programmers to write general routines that can process long lists of data. For example, if every price stored in an accounting program used a different variable name, separate program instructions would be needed to process each price. However, if all the prices were stored in an array, a general routine could be written to process, say, “price(J)”, and, by allowing J to take different values, could then process any individual price.

Collection of numbers (or letters representing numbers) arranged in rows and columns. A matrix is an array shown inside a pair of brackets; it indicates that the array should be treated as a single entity.