接する

1. Origins, structure, and basic meaning

• Structure: 接する (せっする) is a verb used both for dealing with a person and for two areas sharing a boundary.
• Basic usage: 客に接する marks the person dealt with by に, while 川を境に接している describes the continuing adjacency of two areas along a river boundary.

2. Common pitfalls and similar expressions

• Human interaction versus geographical adjacency
  • Read 接する as interpersonal conduct in the first example and geographical adjacency in the second. In particular, 接している does not mean that the two regions are interacting as people.