Does by 2010 for example means before 2010? I read a post here that by Tuesday means before Tuesday. I would like to know are they the same?


  • It can mean "before 2010 is out", that is, "before 2011".
    – TimR
    Sep 16, 2017 at 14:58

1 Answer 1


By [TIMEPOINT] means "no later than [TIMEPOINT]". When [TIMEPOINT] is expressed as a period of time it is ambiguous whether by points to the beginning of the period or its end. If that is not explicitly stated you have to infer the meaning from context.

So by Tuesday does not necessarily mean "before Tuesday"; if I say "You have to finish this report by Tuesday" I probably mean that it has to be submitted sometime during the workday on Tuesday. And by 2010 does not necessarily mean "before 2010"; but if I say "By 2010 John was ready to move on to another job" I probably mean that John was dissatisfied with his current job in 2009 and started looking for another fairly early in 2010.

But neither of those inferences is certain. If it makes a difference in your situation, ask for clarification.

  • Thank you very much for prompt and detailed reply. The sentence is this: "In 2001, English was the predominant language spoken at home by most people in the Cape Peninsula; however, by 2011 it had become less common, .. "
    – Shapol46
    Sep 16, 2017 at 15:15
  • @shapol46 Note that perfect in the second clause: the present perfect is a present tense, and the clause means "In 2011 English was less common". There's no indication of when in 2011 the measure is taken, but over a ten-year period it doesn't really matter: the point is the change. Sep 16, 2017 at 15:53

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