The smallest bit of something which can possibly exist. For example, light energy comes in quanta which are known as photons, and can be thought of as particles of light. You cannot have an amount of light more than nothing but less than one photon.
To use the phrase 'quantum leap' as a monumental jump is extremely funny when you realize that a quantum anything would be the smallest thing imaginable.
An awesomecar made by Volkswagen that was the predecessor to the Passat. Made in the 1980's before being discontinued. Very few are left in existence and only a true badass would drive one.
A quantum is a unit of energy in regards to atoms. More specifically, a quantum is an electron shell surrounding the nucleus of an atom. Larger atoms (those located further down the periodic table) have more electron shells, each of which is known as a quantum.
The valence electrons of lithium (Li) are in the 2nd quantum, while the valence electrons of sodium (Na) are in the 3rd quantum.