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open

open

13 7.8
A range of numbers that does not include its end points
  • adjective
  • /ˈoʊpən/
  • Specialized
translation icon : abierto
  • The set of all points that lie within an open range does not include the boundaries.
  • open rectangle
  • open, not closed

I'm going to cover the space by open sets by open balls.

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Examples

  • So therefore this is now a open circle between zero and two, and that is an open circle.

  • The elements W that are elements of T are called open sets with respect to T.

    Academic text (1998)
  • So this shows that the empty set is open in Y.

  • Following the initial open coding phase of the analysis, 159 open codes were identified.

    Academic text (2014)
  • The sections on experience contained 65 fixed response items and one open-ended question.

    Academic text (2000)
  • In mathematics, an interval is considered open if it does not include its endpoints.

  • An open set in topology is defined as a set that does not contain its limit points.

Antonyms

closed
  • Specialized
7.5

A range of numbers that includes both end points

closed interval
  • Specialized
7.3

All numbers from one number to another including both ends

Idioms

104 2.5

In public and not hidden so other people can see or hear

Watch carefully for danger or a chance

open arms
  • Informal
33 2.8

A warm, eager welcome

To avoid choosing now so other choices remain

Stay half awake and watch for danger while you sleep because you are afraid

4 3.7

Stay alert to hear useful news or information

4 7.7

To create many unexpected problems that are hard to control

eyes wide open
  • Informal
3 4.3

To act while fully aware of possible risks

3 3.7

Make someone understand something they did not know before

3 7.4

Create a difficult situation with many unexpected problems

1 9.9

To attack or punish someone suddenly and violently, often for something they did

to open the kimono
  • Offensive
1 9.9

To show a company's private information to others, often during business talks

Acting while fully aware of what could go wrong

To not pay attention and miss what is happening around you, for example because you are daydreaming

Waste effort arguing about something everyone already agrees with

To try to make something happen when it is already easy or people already agree

To cause a lot of trouble and anger among people

Create new ways to make progress or grow

open sesame
  • Literature
8.6

A magic word that gives easy access or success

Compounds

127 2.3

Completely open and available with nothing stopping access

open-source
  • Specialized
51 3.7

Software that has code anyone can read, change, and share

35 2.7

An event when people are invited to visit and feel welcome

22 3.9

An event where people take turns performing music, poetry, or comedy

18 3.8

Very clear and easy to decide or solve

17 1.1

Completely open with nothing closed or covering it

open letter
  • Literature
16 4.0

A letter written to one person but published for everyone to read to make people notice a problem

open-heart surgery
  • Specialized
16 4.4

An operation where doctors open the chest to operate on the heart

15 1.2

A large area of land without buildings or trees used for play

open book
  • Informal
12 3.5

A person whose feelings and thoughts are easy to understand

12 4.1

A time when an activity is allowed, often for hunting or fishing

11 2.1

Taking place outside and not under a roof

9 4.3

Not strictly controlled, so illegal things can happen

A conversation where people share ideas honestly without holding back

8 1.0

Outside in a place that is not covered

8 3.3

A practice of letting people come in and speak freely to leaders

7 6.2

A marriage in which both partners allow each other to have sex with other people

open society
  • Formal
6 5.1

A community where people can speak freely, join groups, and vote

open secret
  • Informal
6 4.0

Something people try to hide but many already know

5 4.3

An agreement to get goods or services now and pay later

open primary
  • Literature
5 6.4

An early election before the main vote where any registered voter can vote for candidates of only one party

open fracture
  • Specialized
3 5.4

A broken bone that sticks out through a cut in the skin

3 7.2

A way to let many countries trade equally with one country, used for China in the late 1800s

Anyone is welcome to join or take part

A market that takes place outdoors where stalls sell food and other goods

1 3.5

A British university that offers part-time online and distance courses for adults, often without usual entry rules

1 4.1

A room with few dividing walls that makes one big space

open circuit
  • Specialized
1 4.6

A broken electrical path that stops electric current

A way of letting people talk freely to those in charge

A space in a wall where you make an open fire to heat or cook in a room

open frame
  • Jargon
1 7.1

A frame in which a player fails to knock down all the pins with two rolls

open shop
  • Jargon
1 5.2

A workplace where workers do not have to join a union or pay its fees

open weave
  • Specialized
1 4.5

A fabric with threads placed far apart so small holes let light and air through

A shirt with the top button undone at the neck

A way of allowing foreign companies to trade on the same terms as local companies

open-angle glaucoma
  • Specialized
1 5.2

A common eye disease that slowly reduces side vision when eye fluid cannot drain

A piece of bread with toppings and no top slice

open chain
  • Specialized
7.2

A chain of atoms in a molecule whose ends do not join to make a ring

open interval
  • Specialized
8.2

A set of numbers between two points that does not include the end points

A single slice of bread with toppings served without a top slice

open order
  • Specialized
8.0

Soldiers standing with wide spaces between ranks so an officer can walk between them for inspection

open sight
  • Specialized
7.3

A simple part on a gun with an open notch for aiming

open vowel
  • Specialized
5.7

A vowel sound made with the tongue low in the mouth

open syllable
  • Specialized
5.3

A syllable that ends with a vowel sound and usually has a long vowel

An outdoor place where people sell food and crafts

open-class word
  • Specialized
7.4

A type of word that often gets new words, like nouns and verbs

A warm, friendly welcome that makes guests feel wanted

A warm welcome you give by opening your arms to hold someone

open-end credit
  • Specialized
6.2

A borrowing plan that lets you borrow up to a set limit and use it again as you repay

open-end fund
  • Specialized
6.9

A company that sells and buys shares directly at their daily price

8.1

A company that sells and buys back shares any time at a price based on its assets

open-end wrench
  • Specialized
4.5

A tool with two flat open jaws that grip nuts or bolts

open-hearth
  • Archaic
9.5

Steel that people make by heating iron in a large furnace

8.1

A large hot oven that makes steel by heating metal on a shallow bed with flames above

8.2

A way of making steel by melting iron and scrap metal in a large open furnace

Surface Forms

open positive
opener comparative
openest superlative

Etymology

Open in mathematics keeps the basic idea 'not closed', so an open interval does not include its end points. That is why the ends are left out of an open interval.