Spanish -dad and -ion words
As I've been working through my tree and immersion, I've seen that pretty much all of the words ending with -dad and -ion in Spanish are feminine. Is this a rule? Are all words with those endings feminine? Also, are there any rules regarding gender in Spanish that I may want to know?
Yes, there is a rule in Spanish that words ending in -dad, -sión, -tión, and -ción are all feminine. However, words ending in -ma are masculine. Those are what I remember offhand. Of course, for every rule, there are exceptions, so you may find it more helpful to memorize the article along with new vocabulary words. Buena suerte con tus estudios :)
However, words ending in -ma are masculine.
Be careful with this, it only applies to words with Greek origins. Words that come from Latin (cama, pluma, forma), are feminine like you'd expect given their "-a" suffix.
The reason for this is that they come from Latin words that are feminine.. They came into use in English (from Latin, some of them via French) with the endings -ation and -ity.
If you know a word in Latin, you will probably know the word in Spanish, including for many words the gender.
Latin words in -atio (-ationis) are always feminine: natio - nación - nation. So are those in -as (-atis): qualitas (qualitatis) - calidad - quality.
I don't know enough Spanish to tell you any other such general rules, though.
Everyone has given some pretty good answers to your question, but for future reference this is a really great breakdown of gender patterns and the inevitable exceptions.