Englishfor English speakers
external
Adjective
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Something that is external is not on the inside.
Both internal and external stairs need to be modified to allow wheelchairs into the building.
There are many influences upon the child external to life in school.
I wondered if there were any external pressures that led your husband to make the change.
Other sources of external debt arise where non-residents purchase local bonds.
boundary
Noun
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A boundary is the line around something's outside edge.
The elephants have to live within the boundary of the park or risk being shot.
There have been many times in their lives when the boundaries between their personal and professional lives have disappeared.
More manufactured goods are crossing international boundaries every day.
An international commission that regulates the boundary waters between the U.S. and Canada.
radius
Noun
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A radius is a straight line between the centre of a circle and its circumference.
To find the area of a circle, you have to know the length of the radius.