by

Everyday

1. By shows who does something: a book by Roald Dahl. tree →
2. By shows how something is done: by bus, by hand. tree →
3. By means next to: sit by the window. tree →
4. By means not later than: be home by six. tree →
5. In maths, by names the number you multiply or divide by, or how much something changes: grew by 3; a room 4 by 5 metres. tree →
6. As an adverb, by means past: the cars went by. tree →
7. (casual) «Stop by», «drop by», «pop by» mean visit for a short time; «by the way» or «btw» adds a new point. tree →
8. (formal) The exam voice uses «by» in stiff phrases: «by means of», «by virtue of», «increased by a factor of», «by the conclusion of». tree →
9. By design means on purpose, planned in advance. tree →

In the lessons

«multiply … by», «divide … by» (6 divided by 2 = 3); «a room 4 by 5 metres» (sides); «increase by 3» (add 3), «decrease by 3» (subtract 3); also «by Tom» for who did it; in everyday life «by the way», «by myself» (alone), «one by one», «by heart», «by mistake»; in texts «btw»; in the exam voice «by means of», «increased by a factor of 2» (multiplied by 2), «by the conclusion of the week»

Examples

• When there are several equal groups, we multiply the number of groups by the size of one group. tree →
• Divide 20 by 4. tree →
• The cake was cut by Dad into 8 pieces. tree →
• We go to school by bus. tree →
• The plant grew by 3 centimetres this week. tree →
• Please hand in your homework by Friday. tree →
• She sat by the fire to get warm. tree →
• I learned the poem by heart. tree →
• The children came in one by one. tree →
• btw nan's stopping by at 5, set another plate tree →
• Sorry, I took your pen by mistake. tree →
• The quantity is subsequently increased by a factor of 3; determine the resulting value. tree →
• "No, sir, by design," returned Aladdin. tree →

Note

«multiply A by B» = A × B; «divide A by B» = A ÷ B. Trap: «more by 3», «grew by 3» or «increased by 3» means add 3, not multiply; «increased by a factor of 3» means multiply by 3. «4 by 5 metres» names two sides; the area is 4 × 5. «by Friday» is a deadline, not a number. Do not mix «by» with «buy» (pay for) and «bye» (goodbye).

In Jewish tradition

In the Torah it is often used to mean "according to" or "in the order of", as in "by their families". In the primary lessons: «multiply … by», «divide … by» (6 divided by 2 = 3); «a room 4 by 5 metres» (sides); «increase by 3» (add 3), «decrease by 3» (subtract 3); also «by Tom» for who did it; in everyday life «by the way», «by myself» (alone), «one by one», «by heart», «by mistake»; in texts «btw»; in the exam voice «by means of», «increased by a factor of 2» (multiplied by 2), «by the conclusion of the week»

Examples

• And they did eat there by the heap. (Torah GEN.31.46, JPS 1917) tree →
• And Abraham set seven ewe-lambs of the flock by themselves. (Torah GEN.21.28, JPS 1917) tree →
• And the sons of Merari by their families: Mahli and Mushi. (Torah NUM.3.20, JPS 1917) tree →
• They are wholly consumed by terrors. (Writings PSA.73.19, JPS 1917) tree →
• Then Jesse made Shammah to pass by. (Prophets 1SA.16.9, JPS 1917) tree →
• Who can number the clouds by wisdom? (Writings JOB.38.37, JPS 1917) tree →

Note

«multiply A by B» = A × B; «divide A by B» = A ÷ B. Trap: «more by 3», «grew by 3» or «increased by 3» means add 3, not multiply; «increased by a factor of 3» means multiply by 3. «4 by 5 metres» names two sides; the area is 4 × 5. «by Friday» is a deadline, not a number. Do not mix «by» with «buy» (pay for) and «bye» (goodbye).