single

Not accompanied by anything else; one in number.

Can you give me a single reason not to leave right now?

The vase contained a single long-stemmed rose.

Not divided in parts.

The potatoes left the spoon and landed in a single big lump on the plate.

Designed for the use of only one.

a single room

Performed by one person, or one on each side.

a single combat

These shifts refuted, answer thy appellant, […] / Who now defies thee thrice to single fight.

Not married, and (in modern times) not dating or without a significant other.

Forms often ask if a person is single, married, divorced, or widowed. In this context, a person who is dating someone but who has never married puts "single".

Josh put down that he was a single male on the dating website.

A 45 RPM vinyl record with one song on side A and one on side B.

A popular song released and sold (on any format) nominally on its own though usually having at least one extra track.

The Offspring released four singles from their most recent album.

One who is not married or does not have a romantic partner.

He went to the party, hoping to meet some friendly singles there.

A score of one run.

He refused to take a single as the ball was dropped by his opponent's best fielder.

A hit in baseball where the batter advances to first base.

To get a hit that advances the batter exactly one base.

Pedro singled in the bottom of the eighth inning, which, if converted to a run, would put the team back into contention.

To thin out.

Paul went joyfully, and spent the afternoon helping to hoe or to single turnips with his friend.

The seeds did not germinate in many parts of a row until rains in end of June and thunderplumps in first week of July brought them up later in patches, so that no second sowing was necessary, but singling was done by stages.

To take the irregular gait called singlefoot.

Many very fleet horses, when overdriven, adopt a disagreeable gait, which seems to be a cross between a pace and a trot, in which the two legs of one side are raised almost but not quite, simultaneously. Such horses are said to single, or to be single-footed.

To sequester; to withdraw; to retire.

an agent singling itself from consorts

To take alone, or one by one; to single out.

men […] commendable when they are singled