single-n; 5 Senses

Sense Number 1: a unit measure of one

Commentary: SINGLE[+quantity][+unit][+of_one]

Mary ordered a double espresso and John ordered a single.
Do you have any singles in your pocket to pay the bellboy? (single dollar bills)
A single in this hotel will cost $200 a night, and a double will cost $275. (single room)

WordNet 3.0 Sense Numbers: 2

Sense Number 2: unmarried or romantically unattached person

Commentary: SINGLE[+entity][+person][+status][+unattached][+romantically]

The bar is mostly frequented by singles and 20-somethings.
Bob is the only single Mary knows among her male friends.

WordNet 0.0 Sense Numbers: 1b

Sense Number 3: short musical recording with one song

Commentary: SINGLE[+artifact][+recording][+musical][+one_song]

The old vinyl 78 singles had one song on each side.
You can download MP3 singles from your favorite rock groups from this website.

WordNet 0.0 Sense Numbers: 1a

Sense Number 4: baseball play where player makes one base safely

Commentary: SINGLE[+event][+play][+baseball][+arrival][+safe][+one_base][+by_player]

Jones struck out in the first, hit a single in the fourth, and hit a home run in the ninth.
The hit should have only been a single except for an outfield error.

WordNet 3.0 Sense Numbers: 1

Sense Number 5: sports competition played between individuals, not teams

Commentary: SINGLE[+event][+competition][+sports][+between_individuals]

He is one of the top players in the world today, in men's singles.
She played badminton singles in college.

WordNet 0.0 Sense Numbers: 3