1. (a.) Incapable of being divided, separated, or broken; not separable into parts\.

2. (a.) Not capable of exact division, as one quantity by another; incommensurable.

3. (n.) That which is indivisible.

4. (n.) An infinitely small quantity which is assumed to admit of no further division.

a certain an any any one atomic austere bare basic bound up in bound up with chaste coherent cohesive either elementary essential exclusive fundamental homely homespun homogeneous impartible inalienable indiscerptible indissoluble indissolvable individual infrangible infusible inseparable insoluble integral irreducible lone mere monadic monistic monolithic of a piece one plain primal primary pure pure and simple severe simon-pure simple single singular sole solid solitary spare stark unadorned unanalyzable uncluttered undifferenced undifferentiated undividable undivided unified uniform unique unitary whole