(mathematics) The limit of a convergent sequence of rational numbers, whether the limit is a rational number such as 2, -5, or 2/7 or whether the limit is an irrational number such as the square root of two or the circumference of the circle whose radius is one.

(number theory) A number that is the sum of all of its divisors except itself.

(complex analysis, strict sense) A number of the form bi, where b is any real number and i denotes the imaginary unit.

A nuclear weapon. / (by extension) Something that destroys or negates, especially on a catastrophic scale. / A nuclear power station.

(transitive, chiefly US, colloquial) To use a nuclear weapon on a target. / (transitive, chiefly US, colloquial, figuratively) To destroy or erase completely.

Alternative spelling of nuc (“nucleus colony of bees”)

(anatomy, obsolete) Alternative form of nucha (“spinal cord; nape of the neck”)

(chiefly Northern England, archaic) Alternative form of nook (“a corner of a piece of land; an angled piece of land, especially one extending into other land”)

The sequence of digits used to identify a particular destination telephone in a network. / (in the plural, humorous) A large number.

(colloquial) A telephone number.