1. In the neighbourhood of, close to
   "my house is by the church";
   - near
    
2. By means of; with aid of; through the act or agency of
   "destroyed by fire";
   - through
    
3. Used in specifying adjacent dimensions
   "a room ten by twenty metres"
    
4. At some time before; before the end of a given time interval
   "get it done by 9am tomorrow"
    
5. On, in traversing
   "came by the path";
   - along

1. So as to pass a given point
   "every hour a train goes by";
   - past
    
2. In reserve; not for immediate use
   "put something by for her old age";
   - aside, away

Sounds like: buy, bye, bi

Encyclopedia: By, John