noun

• (British spelling, immunology) Alternative spelling of immunization.
  "The larger the number of immunised people in the community the less easy is the spread of disease from one person to another. […] For the purpose of creating ‘herd immunity’, as this process is sometimes called, it is necessary to achieve 80 per cent immunisation of the community."
• (rail transport, electrical engineering) The process of immunising signalling and traction power supplies so they don't interfere with each other.
  ""Secondly, we have to find more cost-effective ways of electrifying. And we've had a real breakthrough in the last couple of years in terms of bridge clearances and immunisation, meaning we've been able to take hundreds of millions of pounds off the cost of electrification."