observatory
A place where stars, planets and other celestial bodies are observed, usually through a telescope; also place for observing meteorological or other natural phenomena.
Dictionary · English 249
Vocabulary ranked by real-world frequency — start with the 1,000 most common words. Definitions adapted from Wiktionary (CC BY-SA 4.0), review in progress.
Tiếng Việt English Idioms & phrases →
Frequency: All Top 1,000 1,001–5,000
oi
Said to get someone's attention; hey.
outdoors
Not inside a house or under covered structure; unprotected; in the open air.
offender
One who gives or causes offense, or does something wrong.
overlap
To extend over and partly cover something.
obese
Extremely overweight, especially: weighing more than 20% (for men) or 25% (for women) over their conventionally ideal weight determined by height and build; or, having a body mass index over 30 kg/m².
outreach
The act of reaching out.
orgasm
A rush of sexual excitement; now specifically, the climax or peak of sexual pleasure, which occurs during sexual activity and which in males may include ejaculation and in females vaginal contractions.
optimism
a tendency to expect the best, or at least, a favourable outcome
optimization
The design and operation of a system or process to make it as good as possible in some defined sense.
outdated
Out of date, old-fashioned, antiquated.
oxide
A binary chemical compound of oxygen with another chemical element.
obsolete
No longer in use or no longer useful; now disused or neglected (often in favour of something newer, better, or more fashionable); outmoded.
optic
Of, or relating to the eye or to vision.
ow
Synonym of ouch (“cry of pain”).
ottoman
An upholstered sofa, without arms or a back, sometimes with a compartment for storing linen etc.
oaks
A stakes race in which entry is restricted to 3-year-old fillies.
Omaha
A member of a tribe of Native Americans currently residing in northeastern Nebraska and western Iowa.
onwards
Onward.
overthrow
To bring about the downfall of (a government, etc.), especially by force; to usurp.
ordinance
A local law, passed by e.g. a city.
orbital
Of or relating to, or forming an orbit (such as the orbit of a moon, planet, or spacecraft).
organism
A discrete and complete living thing, such as animal, plant, fungus or microorganism.
outgoing
Extroverted: talkative, friendly, and social, especially with respect to meeting new people easily and comfortably; outgiving.
overhaul
A major repair, renovation, or revision.
optics
The physics of light and vision: basic optical science.
orphan
A person, especially a minor, both or (rarely) one of whose parents have died.
offend
To hurt the feelings of; to displease; to make angry; to insult.
oo
Any of four Hawaiian birds of the genus Moho, formerly classed with the honeyeaters and now believed to be extinct.
orchard
A garden or an area of land for the cultivation of fruit or nut trees.
organizer
A person who arranges the details of a public event.
overdose
An excessive and dangerous dose of a drug.
oasis
A spring of fresh water, surrounded by a fertile region of vegetation, in a desert.
oddly
In a peculiar manner; strangely; unusually.
oppressed
Subject to oppression.
ouch
An expression of one's own physical pain.
outsiders
A pair of nippers for turning a key in a keyhole from the outside.
outskirts
The area surrounding a city or town; suburb.
overlapping
That overlaps something else
obstruction
The act of obstructing, or state of being obstructed.
odyssey
An extended adventurous voyage, usually in search of home.
om
A sacred, mystical syllable used in prayer and meditation.
onboard
Carried or used on or in a vehicle or vessel.
oneself
A person's self: general form of himself, herself, themself or yourself.
overcoming
The act by which something is overcome, or surmounted.
optimum
The best or most favorable condition, or the greatest amount or degree possible under specific sets of comparable circumstances.
overwhelmingly
In an overwhelming manner; very greatly or intensely.
omitted
Left out; not included intentionally.
overlook
A vista or point that gives a view down toward something else.
outward
Outer; located towards the outside.
overrated
Given an undue amount of credit for quality or merit in a field; not necessarily related to popularity.
off-the-cuff
said or done without preparation
outlaw
A fugitive from the law.
oversee
To survey, look at something in a wide angle.
obedience
The quality of being obedient.
obligated
Committed.
organise
Non-Oxford British standard spelling of organize.
overdue
Late; especially, past a deadline or too late to fulfill a need.
overload
To load excessively.
oof-bird
Recognized English idiom; full definition pending editorial review.