singleton

Only one exists

A singleton is a single item where multiples are possible or expected.

In card games, it's a card that is the only one of its suit in a hand: I was dealt a singleton ace of spades.

More broadly, singleton describes any sole member of a category—a single birth rather than twins, a single child rather than siblings.

In computing, a singleton is a design pattern that restricts a class to one instance.

The word carries a slight sense of unusualness, since the contexts where it appears typically involve groups.

individual

person

Human individual

entityIndependent existing thing
beingExisting as something
soulInnermost animating essence

specimen · unit · one · lone · sole · only · solitary · unaccompanied · standalone · discrete

unique

rare

Seldom found or seen

uncommonSeldom occurring or found
one-of-a-kindHaving no equivalent
exceptionalNotably above the norm

anomaly · outlier · oddity · rarity · curiosity · peculiarity · novelty · aberration · deviation · irregularity

programming

instance

Single occurrence of something

objectTangible entity or aim
classGrouping by shared traits
patternRecurring arrangement or template

design · initialization · constructor · global · static · lazy · eager · thread-safe · anti-pattern · registry

mathematics

set

Arrange in position

elementBasic substance or factor
unitIndividual part or measure
oneLowest positive integer

cardinality · member · subset · trivial · degenerate · tuple · collection · empty · pair · ordered

cardgame

trump

Suit outranking all others

spadesFlat-bladed digging implements
heartsCirculatory system engines
diamondsPrecious crystallized carbon

clubs · bridge · whist · euchre · trick · suit · lead · void · hand · deal

boardgame

stone

Solid earth fragment

spaceUnoccupied area or interval
squareRhombus with right angles
pieceA portion or segment

cell · move · capture · position · isolated · unconnected · territory · liberty · group · chain

solitude

isolation

Complete separation from others

solitudeState of being alone
seclusionVoluntary withdrawal from society
lonelinessState of lacking companions

aloneness · separateness · detachment · withdrawal · reclusiveness · lonesomeness · soleness · oneness · insularity · hermitage

birth

twins

Siblings born simultaneously

tripletsThree born together
quadrupletsFour simultaneous births
quintupletsFive offspring, one birth

sextuplets · septuplets · octuplets · multiple · pregnancy · firstborn · delivery · gestation · conception · fertility

singleton

person

rare

instance

set

trump

stone

isolation

twins

singleton

Opposites

Phrases

Categories

Family