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 The above is a screenshot of Collins Cobuild dictionary explaining the word 'runway'. What bothers me is the definite articles in phrase "the runway is the long strip". Why can't it be just " the runway is a long strip" or "a runway is a long strip" ? Kindly help. Thanks in advance.

closed as off-topic by FumbleFingers, David, tchrist Jul 31 '17 at 14:33

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  • I'm voting to close this question as off-topic because OP is confusing runway (an airport landing strip) with runaway (a fugitive, escapee). – FumbleFingers Jul 31 '17 at 13:57
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    Oh no! That was a typo that crept in. I corrected it. – Sunny Jul 31 '17 at 14:01
  • I don't see where the choice of a or the matters in this example. This could just as easily have been written ...runways are... – Davo Jul 31 '17 at 14:02
  • The dictionary definition given assumes (as is always the case) some prior knowledge, here including the fact that there is (often a single) road-like surface from which planes take off and on which they land at airports. It's assuming that a mental image will be conjured. For larger airports, 'runways are the road-like surfaces ...' would apply. – Edwin Ashworth Jul 31 '17 at 14:20
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    Please do not post screenshots of words; only ever type them in. Otherwise they cannot be searched, copied, etc. – tchrist Jul 31 '17 at 14:33

Once you establish the setting of an airport, it is correct and natural to use definite noun phrases for anything commonly found at an airport, such as

the runway
the control tower
the entrance
the exit
the parking lot
the flight attendant lounge
the fence around the airport

This is because most airports have these things, just like most houses have front doors, walls, stairs, gardens/yards, etc.

As for the long strip of ground with a hard surface, this is also something that the reader can be expected to be able to "identify." For instance if you are looking at an airport from the sky, it's pretty easy to identify it. You could even use the hard surface, but by using a hard surface the sentence is not concerned with whether you can "identify" which hard surface it is; in this case it is similar to saying "any hard surface." On the other hand, you could use a long of ground with a hard surface, but it sounds better to be more definite when, um, defining something.

Note that the sentence says "an aeroplane" because most airports service more than one aeroplane. Here an is similar to one.

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