Oxford Advanced American Dictionary

Definition of rubber noun from the Oxford Advanced Learner's Dictionary

Oxford3000

rubber

noun
rubber pronunciation English ˈrʌbə(r) rubber pronunciation American ˈrʌbər
 
1 [uncountable] a strong substance that can be stretched and does not allow liquids to pass through it, used for making tyres, boots, etc. It is made from the liquid (= sap ) inside a tropical plant or is produced using chemicalsa ball made of rubbera rubber tree see also foam rubber, India rubber2 [countable] (British English) (also eraser North American English, British English) a small piece of rubber or a similar substance, used for removing pencil marks from paper; a piece of soft material used for removing chalk marks from a blackboard3 [countable] (old-fashioned, informal, especially North American English) = condom4 [countable] (in some card games or sports) a competition consisting of a series of games or matches between the same teams or players
Idioms

where the rubber meets the road

(North American English) the point at which something is tested and you really find out whether it is successful or true Here's where the rubber meets the road: will consumers actually buy the product?
more at burn rubber at burn verbrubber adjective [usually before noun]a rubber ballrubber gloves