swab

¹ American  

[swob] / swɒb /

noun

1. a large mop used on shipboard for cleaning decks, living quarters, etc.

2. a bit of sponge, cloth, cotton, or the like, sometimes fixed to a stick, for cleansing the mouth of a sick person or for applying medicaments, drying areas, etc.

3. the material collected with a swab as a specimen for microscopic study.

4. a brush or wad of absorbent material for cleaning the bore of a firearm.

5. Slang. a sailor; swabby.

6. Slang. a clumsy fellow.

---

verb (used with object)

swabbed, swabbing

1. to clean with or as if with a swab.

   to swab the decks.

2. to take up or apply, as moisture, with or as if with a swab.

   to swab soapy water from the decks.

3. to pass over a surface.

   to swab a mop over the decks.

Swab. ² American  

abbreviation

1. Swabia.

2. Swabian.

---

swab British  

/ swɒb /

noun

1. med

   1. a small piece of cotton, gauze, etc, for use in applying medication, cleansing a wound, or obtaining a specimen of a secretion, etc

   2. the specimen so obtained

2. a mop for cleaning floors, decks, etc

3. a brush used to clean a firearm's bore

4. slang an uncouth or worthless fellow

---

verb

1. (tr) to clean or medicate with or as if with a swab

2. to take up with a swab

Other Word Forms

• unswabbed adjective

Etymology

Origin of swab

First recorded in 1645–55; back formation from swabber

Explanation

If a pirate tells you to swab the deck, get out the mop! A swab is a piece of absorbent material on a stick, like a mop, but it can also be small, like a cotton swab used for cleaning ears. As a verb, to swab means to use a swab. So if you're a nurse assisting a surgeon, you might swab an incision, and if you're working on crime scene, you might swab the area for clues. On land, a swab is usually a small piece of cotton, but the original meaning of the noun was "mop used on a ship," and for a while it was also a popular derogatory term for a low-ranking sailor.

Example Sentences

Investigators took a swab from a leftover pizza crust Heuermann threw out in 2023, linking him to a hair found on the burlap sack Waterman’s remains were found in.

From The Wall Street Journal • Apr. 8, 2026

Screening may be done non-invasively, via saliva or a cheek swab, and women who get a negative result are cleared to compete for the rest of their lives.

From The Wall Street Journal • Mar. 29, 2026

The test requires screening through saliva, a cheek swab or a blood sample.

From Los Angeles Times • Mar. 26, 2026

A friend convinced him to head to hospital where concerned emergency ward staff put him on oxygen - but the penny dropped when a medic rubbed his arm with a swab that turned blue.

From BBC • Mar. 13, 2026

He returned the comb to his pocket, stepped off the tins and put them back with the bottle and swab and broom.

From "The God of Small Things" by Arundhati Roy

Related Words

• daub
• mop