When a person attends any convention which is related to business incur some Expenses such as travelling and food etc. All these Expenses are tax deductible and are called convention Expenses.
If you are working in a company and are asked to attend some kind of convention you will notice that the company will ask you to bring all the receipts of the transactions which are made by you during that period. Companies actually benefit from these Expenses. Sometimes you will notice that whenever a person goes to attend such meeting the company arranges lavish arrangements for them and tend to increase the Convention Expenses.