Yes, series is a Scrabble word!

Noun

1. Similar things placed in order or happening one after another

2. A serialized set of programs

3. A periodical that appears at scheduled times

4. (sports) several contests played successively by the same teams

5. (electronics) connection of components in such a manner that current flows first through one and then through the other

6. A group of postage stamps having a common theme or a group of coins or currency selected as a group for study or collection

7. (mathematics) the sum of a finite or infinite sequence of expressions