The term "pro-rata" comes from the Latin word for ‘proportional’. It’s about distributing something evenly, depending on how much effort a person puts in. So, to put it simply, pro-rata in terms of holiday entitlement means that figures are calculated from what you would have accrued if you were working full time but reduced to be proportional to the number of hours you actually worked. The proportion of holidays will depend on how much an employee works, relative to a full-time employee. For example, if they work half as much, they are entitled to half as much holiday.