Tangency and Wiper arm

Tangency noun - The state of being tangent; having contact at a single point or along a line without crossing.

Wiper arm and tangency are semantically related. In some cases you can replace phrase "Wiper arm" with "Tangency", this terms are similar.

Wiper arm noun - Contact consisting of a conducting arm that rotates over a series of fixed contacts and comes to rest on an outlet.

Tangency and wiper arm are semantically related. You can use "Tangency" instead a noun phrase "Wiper arm".