Yes, mass is a Scrabble word!

Verb

1. Join together into a mass or collect or form a mass

Adjective

1. Formed of separate units gathered into a mass or whole

Noun

1. The property of a body that causes it to have weight in a gravitational field

2. (often followed by `of') a large number or amount or extent

3. An ill-structured collection of similar things (objects or people)

4. (Roman Catholic Church and Protestant Churches) the celebration of the Eucharist

5. A body of matter without definite shape

6. The common people generally

7. The property of something that is great in magnitude

8. A musical setting for a Mass

9. A sequence of prayers constituting the Christian Eucharistic rite