bicycloannulation
/ˌbʌɪˈsʌɪkləʊˌanjʊˈleɪʃn/ /ˌbʌɪˈsɪkləʊˌanjʊˈleɪʃn/Chemistry
noun
A process in which a molecule undergoes one or more addition reactions leading to the formation of two adjoining rings.
Origin
1970s. From bi- + cyclo- + annulation.