imaginary

Plural: imaginaries

Noun

(mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of -1
Imagination; fancy.
An imaginary number.
The set of values, institutions, laws, and symbols common to a particular social group and the corresponding society through which people imagine their social whole.

Adjective Satellite

not based on fact; unreal; - F.D.Roosevelt
- "a small child's imaginary friends"

Adj

Existing only in the imagination.
Having no real part; that part of a complex number which is a multiple of √ (called imaginary unit).
Having no real part; that part of a complex number which is a multiple of √ (called imaginary unit).

Examples

imaginary friend
Unicorns are imaginary.

Origin / Etymology

From Middle English ymaginarie, ymagynary, from Latin imāginārius (“relating to images, fancied”), from imāgō, equivalent to imagine + -ary.
The mathematical sense derives from René Descartes's use (of the French imaginaire) in 1637, La Geometrie, to ridicule the notion of regarding non-real roots of polynomials as numbers. Although Descartes' usage was derogatory, the designation stuck even after the concept gained acceptance in the 18th century.

Synonyms

complex number, complex quantity, fanciful, imaginary number, notional, all in one's head

Scrabble Score: 15

imaginary: valid Scrabble (US) TWL Word
imaginary: valid Scrabble Word in Merriam-Webster MW Dictionary
imaginary: valid Scrabble Word in International Collins CSW Dictionary

Words With Friends Score: 17

imaginary: valid Words With Friends Word