Yep. 26 episodes is 1 full season. Most anime (except for those insanely long running ones, like DBZ, Naruto, Sailor Moon, etc.) are 1 season. Some are even less. Rec is something like 10 10 minute episodes, and there are others (I can't think of any right now).
Sometimes you get ones that are only 13 episodes.
Oh, and there are OVAs, which run anywhere between 1 and 5 or 6 (I haven't heard of/watched anything with more than 5, and that was the Ah! My Goddess OVAs).