elimination

https://doi.org/10.1351/goldbook.E02038
The reverse of an addition reaction or transformation. In an elimination two groups (called eliminands) are lost most often from two different centres (1/2/elimination or 1/3/elimination, etc.) with concomitant formation of an unsaturation in the molecule (double bond, triple bond) or formation of a new ring. If the groups are lost from a single centre (α-elimination, 1/1/elimination) the resulting product is a carbene or a 'carbene analogue'.
See also: α-elimination
Source:
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1112 (https://doi.org/10.1351/pac199466051077)