participant; entrant; player; competitor
nonparticipation; nonattendance
entry qualifications; joining qualifications
free-for-all; open-to-all; optional (to participate in); non-compulsory
entrance fee; participation cost
participation award; prize for participation
those interested in participating; persons wishing to participate
participatory; participating; hands-on
possibility of participation; participation possibility
application (to take part in); registration
to call for someone's participation
free-for-all; open-to-all; optional (to participate in); non-compulsory
capital participation; equity participation
participation in politics; political participation
you are cordially invited to participate; please come and join us
you are cordially invited to participate; please come and join us
to call for someone's participation
you are cordially invited to participate; please come and join us
attending a meeting; participating in a meeting
resident participation; citizen participation; public involvement (in local governance)
citizen participation; public participation; popular participation
you are cordially invited to participate; please come and join us
labor participation in management (labour)
intervener; intervening party; third-party intervener
number of participants; number of people present
legal system permitting victim participation in the criminal justice process
audience participation program (programme)
participation fee; entry fee
auxiliary intervention (in a lawsuit)