How are head and neck cancers staged and what, exactly, does that mean?

Standardized. There are several staging protocols, but the american joint commission on cancer staging (ajcc) is the biggest one in the United States. By standardizing exactly how a tumor is "staged" is based on the tumor location, size and extent of invasion, whether or not lymph nodes are affected, and if there is distant metastatic disease. These are put together to give a stage: used for treatment decisions.
Thoroughly. Staging refers to the process of finding the extent of cancer, that is, where the cancer has spread to. Typically, head and neck cancer stages are early, locally advanced or distant spread. The process involves detailed exams (using laryngoscopy too); scans (ct, MRI or pet) and sometimes multiple biopsies.