The rack rate is the official list price for a room — historically the rate posted at the front desk. It is the reference point most other rates are built from: discounts, packages, and OTA promotions are usually expressed as a reduction from it.
Few guests actually pay the rack rate; it functions as the anchor. A clear rack rate makes the value of a direct-booking perk or a longer-stay discount legible — the guest can see what they are saving against the standard price.
Why it matters for direct booking
On your own booking website you set the rack rate and decide what comes off it. That control — rather than an OTA's promotions discounting your rate for you — is part of owning your pricing and protecting your margin on direct bookings.