2.273 USAGE NOTE

If you want to describe fully the size of an object or area, you can give its dimensions; that is, you give measurements of its length and width, or length, width, and depth. When you give the dimensions of an object, you separate the figures using 'and', 'by', or the multiplication sign 'x'.

• ...planks of wood about three inches thick and two feet wide.
• The island measures about 25 miles by 12 miles.
• Lake Nyasa is 450 miles long by about 50 miles wide.
• The box measures approximately 26 inches wide x 25 inches deep x 16 inches high.

If you are talking about a square object or area, you give the length of each side followed by the word 'square'.

• Each family has only one room eight or ten feet square.
• The site measures roughly 35 feet square.
• ...a farm covering 300 square miles.

'Cubic' is used in front of units of length when expressing volume.

• The brain of the first ape-men had been about the same size as that of a gorilla, around 500 cubic centimetres.

You express temperature in degrees, using either degrees centigrade, or degrees Fahrenheit. Note that in everyday language the metric term centigrade is used to indicate temperature, whereas in scientific language the term celsius is used which refers to exactly the same scale of measurement.

2.274

You talk about the speed of something by saying how far it can travel in a particular unit of time. To do this, you use a noun such as 'mile' or 'kilometre', followed by 'per', 'a', or 'an', and a time noun.

• The car could do only forty-five miles per hour.
• Wind speeds at the airport were 160 kilometres per hour.
• Warships move at about 500 miles per day.