'cyclisation' originates from modern scientific English formation, ultimately from the Greek element 'kuklos' (κύκλος) meaning 'circle' combined with the verb-forming suffix '-ize' (via Latin/French) and the noun-forming suffix '-ation/‑isation'.

'kuklos' (Greek 'circle') gave the combining form 'cyclo-' in New Latin/modern scientific usage; this combined with '-ize' to form 'cyclize' (verb) and then with '-ation/‑isation' to form the noun 'cyclization'/'cyclisation' used in chemistry.

Initially built to mean 'making into a cycle or ring' in technical/scientific contexts; it has remained specialized with the current meaning 'formation of a ring (in a molecule)'.