1. (of an event) come to pass in time, so that it is real and actual at some time
   "What is happening?";
   - hap [archaic], go on, pass off, occur, pass, fall out, come about, take place
    
2. Come into being; become reality
   "Her dream really happened";
   - materialize, materialise [Brit]
    
3. Occur or be the case in the course of events or by chance
   "It happens that today is my birthday";
   - befall, bechance [archaic]
    
4. Chance to be or do something, without intention or causation
   "I happen to have just what you need!"
    
5. Come upon, as if by accident; meet with
   "I happened upon the most wonderful bakery not very far from here";
   - find, chance, bump, encounter

Derived forms: happening, happened, happens

Type of: bump into, come across, encounter, meet, run across, run into, see