* Noun: If you're referring to the company, it's a noun. For example: "Adobe released a new version of Photoshop."
* Noun: If you're talking about the material, it's also a noun. For example: "The house was built with adobe bricks."
* Adjective: If you're describing something as being made of adobe, it functions as an adjective. For example: "The walls were adobe."
To determine the part of speech, look at how the word is used in the sentence.