a multiple of the square root of minus one, which is denoted by i or j -- depending on whether you were trained as a scientist or an engineer

a number in the form bi, where i is infinity

a number that, when squared, produces a real number having a negative value

a number which gives a negative real number if multiplied by itself

a quite reasonable thing to get in this case--it is just that some numbers are multiplied by the square root of negative one, and that is OK

Any positive root of a negative number, as in the fourth root of -3.

The square root of a negative number is an imaginary number. It can be expressed in the form i where is a real number and i = Examples: 2i, -3. 4i, ( = i ) are imaginary numbers. (See also number and complex number.)

An imaginary number is a number in the form bi, where i is the square root of negative one and b is a real number

Multiple of the square root of -1, a number which may be an aid in certain calculations, but which cannot represent a measurable (real) value. i=sqrt(-1) Incoherence Property of a bundle of waves whose relative phases are varying statistically (examples: sunlight, light bulb), as opposed to coherent waves .

A number forming the latter component of a complex number of the form A+Bi,where i is the square root of -1.

A complex number that is not real.

In mathematics, an imaginary number (or purely imaginary number) is a complex number whose square is a negative real number. Imaginary numbers were defined in 1572 by Rafael Bombelli. At the time, such numbers were thought not to exist, much as zero and the negative numbers were regarded by some as fictitious or useless.