mor·tar·board 
(môrtər-bôrd′)
(môrtər-bôrd′)n.
1. A square board with a handle used for holding and carrying masonry mortar.
2. An academic cap topped by a flat square.
mortarboard- senescent
- seneschal
- Senghor
- senile
- senile dementia
- senilely
- senility
- senior
- senior airman
- senior chief petty officer
- senior citizen
- senior-citizen
- senior citizenry
- senior high school
- senioritis
- seniority
- senior lecturer
- senior master sergeant
- senior moment
- seniti
- Senlac
- senna
- Sennacherib
- sennachie
- sennachie