1) Bonus 2) Fee 1) Business term 2) Monetary element 3) Payment to a guest speaker 4) Reward 
An honorarium is an ex gratia payment (i.e., a payment made without the giver recognizing themselves as having any liability or legal obligation) made to a person for their services in a volunteer capacity or for services for which fees are not traditionally required. This is used by groups such as schools or sporting clubs to pay coaches for thei...
• (a.) Alt. of Honorary
Money or other valuable property given in gratitude for services rendered; for example, payments to ministers for presiding at weddings and funerals or to politicians for speaking at a trade group's convention.
[n] - a fee paid for a nominally free service
a payment in recognition of acts or professional services for which custom or propriety forbids a price to be set: The mayor was given a modest honorarium for delivering a speech to our club. · a fee for services rendered by a professional person.