Biochemistry

La cascata di segnali is one of the few terms on this page where the English reader is looking at a loan that travelled the other way. « Cascade » entered English in the seventeenth century, by way of French, from the Italian cascata, and it arrived as a word for garden waterworks long before it described anything abstract. What is worth having is where the Italian noun itself comes from. It is built on cascare, and cascare is no literary verb: it is the ordinary, slightly homely word for falling over. Mi è cascato il telefono is my phone fell. Caschi il mondo is come what may. Cascare dal sonno is to be dropping with sleep. So una cascata di segnali lands on an Italian ear more plainly than « a signalling cascade » lands on ours: there is nothing learned about it, only one thing tumbling into the next, which is exactly the picture the biochemistry wants. The borrowing kept the shape of the word and left the household verb behind.