1.  fate;  destiny (esp. as a mysterious force that binds two people together)
2.  relationship (e.g. between two people);  bond;  link;  connection
3.  family ties;  affinity
4.  opportunity;  chance (to meet someone and start a relationship)
when read as "えん"
5.  pratyaya (indirect conditions, as opposed to direct causes)
when read as "えん"
6.  narrow open-air veranda
also written as 椽
when read as "えん"