Criterion for the day of the week of the booking start date.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v26/common/criteria.proto)

| Fields ||
|---|---|
| ## `day_of_week` | `https://developers.google.com/google-ads/api/reference/rpc/v26/DayOfWeekEnum.DayOfWeek` The day of the week. |