catena
catena
n.,
pl. 3nae 73nc8 5L, CHAIN6 a linked or connected series, as of excerpted writings

A catenary is the curve assumed by a chain hanging between two fixed points.
Concatenation is means a seires of linked bojects or subjects

Interesting, Dr. Bill. In Spanish, cadena is a chain of any sort, including crochet.

I believe catenary is also the term for the elevated wires of an electric train system.

Dear consuelo: the wires do indeed assume the catenary curve. That is so much taken for
granted that I had never heard the word in that connection. These days trains with overhead
trolleys and wires are uncommon. I think I remember a time when some cities made railroads
through the city be elctric, but haven't ridden a train in a long time. I did find one URL confriming
your statement:"The overhead wires, known as catenary wires, deliver power to the electric train
as it travels along the track. Given the distances involved, this is a more significant undertaking in
an intercity application than within a city."

There is a new high speed railway being built in the UK to run from London to the Channel Tunnel. It is powered by overhead power lines and that part of the system is indeed called 'the catenary'.