Yes, spider is a Scrabble word!

Noun

1. Predatory arachnid with eight legs, two poison fangs, two feelers, and usually two silk-spinning organs at the back end of the body; they spin silk to make cocoons for eggs or traps for prey

2. A computer program that prowls the internet looking for publicly accessible resources that can be added to a database; the database can then be searched with a search engine

3. A skillet made of cast iron