/nooh"klee euhr, nyooh"-/ or, by metathesis, /-kyeuh leuhr/ , adj.
1. pertaining to or involving atomic weapons: nuclear war.
2. operated or powered by atomic energy: a nuclear submarine.
3. (of a nation or group of nations) having atomic weapons.
4. of, pertaining to, or forming a nucleus.
5. of, pertaining to, or like the nuclear family: nuclear bonds.
n. Informal.
6. nuclear energy: switching to nuclear as a power source.
[ 1840-50; NUCLE(US) + -AR 1 ; cf. F nucléaire ]
Pronunciation . In pronouncing NUCLEAR, the second and third syllables are most commonly said as /-klee euhr/ , a sequence of sounds that directly reflects the spelled sequence -CLEAR. In recent years, a somewhat controversial pronunciation has come to public attention, with these two final syllables said as /-kyeuh leuhr/ . Since /-klee euhr/ , the common pronunciation of -CLEAR, might also be represented, broadly, as /-kleuh yeuhr/ , the /-kyeuh leuhr/ pronunciation can be seen as coming from a process of metathesis, in which the /l/ and the /y/ change places.
The resulting pronunciation is reinforced by analogy with such words as molecular, particular, and muscular, and although it occurs with some frequency among highly educated speakers, including scientists, professors, and government officials, it is disapproved of by many.