Yes, second is a Scrabble word!

Adverb

1. In the second place

Verb

1. Give support or one's approval to

2. Transfer an employee to a different, temporary assignment

Adjective

1. Coming next after the first in position in space or time or degree or magnitude

2. A part or voice or instrument or orchestra section lower in pitch than or subordinate to the first

Noun

1. 1/60 of a minute; the basic unit of time adopted under the Systeme International d'Unites

2. An indefinitely short time

3. The fielding position of the player on a baseball team who is stationed near the second of the bases in the infield

4. A particular point in time

5. Following the first in an ordering or series

6. A 60th part of a minute of arc

7. The official attendant of a contestant in a duel or boxing match

8. A speech seconding a motion

9. The gear that has the second lowest forward gear ratio in the gear box of a motor vehicle

10. Merchandise that has imperfections; usually sold at a reduced price without the brand name