Yes, grand is a Scrabble word!

Adjective

1. Of behavior that is impressive and ambitious in scale or scope

2. Of or befitting a lord

3. Rich and superior in quality

4. Extraordinarily good or great; used especially as intensifiers

5. Of high moral or intellectual value; elevated in nature or style

6. Large and impressive in physical size or extent

7. The most important and magnificent in adornment

8. Used of a person's appearance or behavior; befitting an eminent person

Noun

1. The cardinal number that is the product of 10 and 100

2. A piano with the strings on a horizontal harp-shaped frame; usually supported by three legs