Why is "table's row/leg/dimensions/size (and many more)" correct but not "(the) car's radio" please? Is there any clear rule on using the possessive s in English please?
closed as unclear what you're asking by Hot Licks, NVZ, tchrist♦, curiousdannii, MetaEd♦ Apr 25 '16 at 14:17
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If you are talking about the leg of a specific table or the radio of a specific car then it's "the table's leg" or "the car's radio". If you are talking about a leg or a radio, and you want to qualify its type, you say "the table leg" or "the car radio".
In the first case you're talking about something that "belongs" to something else. In the second case you're using "table" and "car" as adjectives to identify the type of object.
As a general rule, I'd say that as long as something is an integral part or relating to the features of something (the car's radio, a table's leg, the table's dimensions, the boy's nose...) or when it is in someone's possession, even if only temporarily, (Arthur's sword, John's pen, Martha's coffee...) then you should use the possessive 's. When in doubt try to construct the sentence with "of" so instead of "Y's X", try "the X of (the) Y" as in "the radio of the car" or "the sword of Arthur". I've yet to come across a phrase where that is not possible.
For me, the first group sounds strange as well. I'd go for "table size" in general or "size of the table" for a specific table. If you insist, yes, it could be ok in casual talks. The possessive relation is acceptable. (Row, leg, dimensions, and size are part or property of the possessor)
However, in "(the) car's radio", car is not a clear (or generally acceptable) possessor of the radio. Normally, radio works independently and is not a part of car, even though it is slightly/temporarily attached/located at dashboard. We do not say table's bowl, when a bowl is on a table.