Meaning of BUFFER in English

(PROTECTOR) [noun] [C] - something or someone that helps protect from harmFriends are excellent buffers in times of crisis.I bought a house as a buffer against inflation.On a railway a buffer is either of the two protective metal parts at the front and back of a train that reduce damage if it hits something. There are also usually two buffers at the end of a track.A buffer is also a chemical that keeps a liquid from becoming more or less acidic.A buffer state is a peaceful country between two larger countries that reduces the chances of war between them.

Cambridge English vocab.      Кембриджский английский словарь.