What does it mean - …

Suitable accommodation for a spouse visa is accommodation that meets the requirements set out in Immigration Rules Appendix FM: Family members. Specifically, this includes:

1. An accommodation that is available on a commercial or private basis and, which is 1 bedroom for a couple or 2 siblings aged 10 or over of the same gender, or 2 bedrooms for couples with a child.
2. Facilities such as a living area, kitchen and a toilet and bath/shower.
3. The accommodation should have a safe cooking and hot water supply, heating, electrical lighting and ventilation.
4. The accommodation should not be overcrowded.

Sources:

onlineimmigrant.com

gov.uk