That which cannot be divided or split.
An infinitely small quantity which is assumed to admit of no further division.
Incapable of being divided; atomic.
Incapable of being divided by a specific integer without leaving a remainder.
A thing without a like; something unequalled or unparallelled; one of a kind.
Of a rare quality, unusual.
Being the only one of its kind; unequaled, unparalleled or unmatched.
Of a feature, such that only one holder has it.
Particular, characteristic.