The way your paid holiday builds up over the course of a leave year as you work, rather than being available as a single lump sum on day one. How it accrues, and how quickly, depends on whether you work fixed or irregular hours.
In practice
For example, an irregular hours worker's leave accrues at 12.07% of the hours they actually work in each pay period, building up gradually rather than all at once.
See also
Legislation covered