https://doi.org/10.1351/goldbook.C00963
The abstraction, by the radical end of a growing chain-polymer, of an atom from another molecule. The growth of the polymer chain is thereby terminated but a new radical, capable of chain propagation and polymerization, is simultaneously created. For the example of alkene polymerization cited for a chain reaction, the reaction: 
represents a chain transfer, the radical Cl3C· inducing further polymerization: 
The phenomenon occurs also in other chain reactions such as cationic polymerization.
See also: telomerization