Academic writers should not use concatenation loosely. You will sometimes see it used in the broad sense of 'combination', or 'collection', of events, phenomena, etc. Concatenation is derived from the Latin catena, 'a chain': the image is of things that are linked con, 'together'. Properly used in English, it should always indicate a linked series. This is usually a chronological series of events, with some kind of explanatory power - cause and effect, for example.
- The adjective catenary is also derived from catena. It is most often used to define a curve: the sag of a chain, or another flexible heavy connector. The supporting cables of a suspension bridge form a catenary curve. More precisely, OED defines the absolute, or substantive, use of catenary (as a noun) as "The curve formed by a chain or rope of uniform density hanging freely from two fixed points not in the same vertical line. The common catenary is the curve so formed by a chain of uniform thickness."