Is “Mastaba” a Scrabble word?

1.A wide stone bench built into the wall of a house, shop etc. in the Middle East.

2.A rectangular structure with a flat top and slightly sloping sides, built during Ancient Egyptian times above tombs that were situated on flat land. Mastabas were made of wood, mud bricks, stone, or a combination of these materials. Some are solid structures, while others can contain one or more rooms, sometimes decorated with paintings or inscriptions.

“The pyramids at Giza are flanked by large cemeteries containing hundreds of mastabas.”