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an unknown quantity

A person or thing that is unpredictable and thus difficult to anticipate. We're still revising our new product, so its potential success is an unknown quantity. This is her first year teaching, so her ability to connect with her students is still an unknown quantity.
See also: quantity, unknown

unknown country

A place, topic, or situation that is totally foreign or unfamiliar. There has been such turbulence and change with the company that the future now looks like an unknown country. Visiting my dad's family down in Texas always felt like traveling to an unknown country as a kid.
See also: country, unknown

unknown to (one)

With someone being unaware (of something). Unknown to Jacobson, the other two partners had drawn up the deal in such a way that they would have full control of the company in two years' time. My wife invited her entire family to come stay with us for Christmas—unknown to me.
See also: unknown

*unknown quantity

Fig. a person or thing about which no one is certain. (*Typically: be ~; become ~.) John is an unknown quantity. We don't know how he's going to act. The new clerk is an unknown quantity. Things may not turn out all right.
See also: quantity, unknown

unknown quantity

An unpredictable person or thing, as in We don't know how the new pitcher will do-he's an unknown quantity. This expression comes from algebra, where it signifies an unknown numerical value. Its figurative use dates from the mid-1800s.
See also: quantity, unknown

an unknown quantity

COMMON If someone or something is an unknown quantity, not much is known about them. She had met Max several times, but he was still pretty much an unknown quantity. The team is something of an unknown quantity, having played few big games. Ballet was an unknown quantity in the United States at that time.
See also: quantity, unknown

unknown country

an unfamiliar place or topic.
The Latin equivalent, terra incognita , is also used in English.
See also: country, unknown

unknown quantity

a person or thing whose nature, value, or significance cannot be determined or is not yet known.
See also: quantity, unknown

an ˌunknown ˈquantity

a person or thing that you do not know anything or enough about: His ability to make decisions in a crisis is an unknown quantity.Our new director is still an unknown quantity.
See also: quantity, unknown

unknown to somebody

without the person mentioned being aware of it: Unknown to me, he had already signed the agreement.
See also: somebody, unknown
References in classic literature ?
The unknown here again darted at Cropole one of his withering glances.
The unknown himself shut the door after him, and when left alone, looked mournfully at the bottom of the purse, from which he had taken a small silken bag containing the diamond, his last resource.
According to details, unknown robbers entered in the house of Shehzad a resident of the area and looted gold jewellery besides Rs 5,000 cash.
Other unknown unknowns include the size of the vehicle fleet in an automated driving structure where vehicles have much higher utilization rates.
Material and Methods: Total of 94 patients reporting with pyrexia of unknown origin at MH Rawalpindi underwent bone marrow examination.
Illuminated Denbigh High Street, date unknown The butchers in Holywell date unknown (left) the old F Williams site and a general view, date unknown Showing off a newly-decorated Denbigh High Street (left) and a look at how it appears now (right)
If I tried to give an example of an unknown known, then it would not be unknown, it would be known, hence a known known.
Third row down: Unknown, Unknown, Unknown, Cris Colbourne, Unknown, Unknown, Unknown, Unknown, Eric Badgenadge, Unknown.
Now we are venturing into the realm of ''unknown unknowns.
Put some of the unknown fluid in a jar with a little water and shake it.
Different ratios of known to unknown items for drill tasks have been suggested including 70% to 85% known and 15% to 30% unknown (Gickling & Thompson, 1985), 10% unknown to 90% known (Tucker, 1989), 30% unknown to 70% known (Coulter & Coulter, 1990), and 50% unknown to 50% known (Neef; Iwata.
A controversial manuscript since its first publication in 1890, The Unknown Life of Jesus is the original text of Nicolas Notovitch's efforts to learn of the years of Jesus' life unaccounted for in the Bible--when he was between the ages of 13 and 29.
Edward E Younger, who was wounded in combat and highly decorated, selected the Unknown Soldier of WWI from four identical caskets at the city hall in Charlons-sur Marne, France, on October 24, ]921, by placing a spray of white roses on one of the caskets.
This study reviews the available evidence on unknown pathogenic agents transmitted in food and examines the methods that have been used to estimate that such agents cause 3,400 deaths per year in the United States.
And that job becomes particularly formidable when an element of the unknown is factored into the equation.