As a Noun: 1. Joining in or taking part in the NDIS. English = participation. 2. A person who takes part in the NDIS. English = participant. As a Verb or Adjective: 1. To join in or take part in the NDIS. English = participate. Note: 1. Some signers use this initialised form of ‘involve’ (using the one-handed letter for ‘P’) to mean only the English words ‘participant’, ‘participate’ or ‘participation’ when talking about the National Disability Insurance Scheme (NDIS).