# What time does "by the time" mean?

What does it mean "by the time he was six he had learnt to play piano"?

I have searched in the dictionary for a definition of "by" but I don't get the concept in the case of "by" referred to time. I have made some hypothesis about the meaning of the phrase above:

Does it mean during the time before he was six, nearly the time he was six, immediately before he was six, immediately after he was six, meanwhile he was six or something else?

• please give more context so as to receive a more precise answer. Jan 8, 2017 at 12:13
• You may want to edit your question to include what you've done to try to find the meaning yourself. I know the dictionary definition of "by" is very confusing. Jan 8, 2017 at 12:14
• One more bit of advice then I'll stop annoying you :) I'm really glad you got an answer you liked so quickly, but you might want to wait a while before selecting an answer. This post on meta explains some reasons why: Not so fast! (When should I accept my answer?) Jan 8, 2017 at 12:36
• ok, I'll wait :) you are right Jan 8, 2017 at 12:46
• Try Collins, 7; or M-W, 3b; or Oxford, 4. Jan 8, 2017 at 15:34

by the time establishes an end-point or end-range. It is used in constructions where the speaker wishes to say that something had happened (or will have happened) not later than the time specified. You can think of it as "<= the specified time", i.e. earlier than or equal to the specified time.

This traffic is terrible. By the time we get to the theater, the movie will be halfway over.

By the time the parents got home, the baby was already asleep.

By age three, she could recite the first 100 decimal points of π.

The lack of specificity you refer to in your question has nothing to do with the preposition by. All of the vagueness is in the time-phrase. In "by age three", age three really means something like "as a three-year old". She might have been 3-1/2, or even approaching the age of four.

I want you to be here by 10AM sharp.

There is no vagueness there. You should be here not later than 10:00:00.

By the time the clock struck twelve, the coach had turned into a pumpkin.

The coach was fully a pumpkin when then last chime sounded, or possibly when the first chime sounded. It depends on how you understand "struck twelve".

It is probably easiest for me to define this idiom by giving a some example sentences and their meanings.

'By the time Joe was 10 he was driving the family car.


Joe in this case may have learned to drive a bike or tractor before he was 10 years old, but when he was 10 years old he already had the skill to drive the family car.

'By the time Frank was 16 he was already robbing banks.


Frank probably started stealing candy from babies at a much younger age and was so good at performing all kinds of robbery that he had graduated to bank robbery and was doing so at the age of 16.

The idiom 'by the time he/she/it was [number; usually years]' is usually used to point out something unusual about someone or something, often that they are doing something at an unusually younger age than normal.

The actual meaning is that the person is doing the specified activity at the age mentioned (usually in years), but the implication is that they may have been studying or learning that skill at a younger age in order to have the skill they have now.

By the time I was 10, I already knew how to operate a computer.

What that means is that when I was 10 years old I already knew how to work at the computer. In other words, if you could travel back in time and you went to my birthday party when I just turned 10, you could see that I had already acquired all the necessary knowledge one needs to operate a personal computer on a fluent level. It's that simple.