As opposed to haikus, senryuus don't need to include a word that represents the season, and are considered to be a form of poetry in spoken language that satirizes topics such as people and society
Haiku and senryuu are two types of Japanese poems written in a 5-7-5 syllable (or rather, mora) pattern. Other than what's said above. In essence, senryuu can be thought of as the "less formal and dignified" version of haiku.
