A ridge is a long, narrow, elevated geomorphologic landform, structural feature, or a combination of both separated from the surrounding terrain by steep sides. The sides of a ridge slope away from a narrow top, the crest or ridgecrest, with the terrain dropping down on either side. The crest, if narrow, is also called a ridgeline. Limitations on the dimensions of a ridge are lacking. Its height above the surrounding terrain can vary from less than a meter to hundreds of meters. A ridge can be either depositional, erosional, tectonic, or a combination of these in origin and can consist of either bedrock, loose sediment, lava, or ice depending on its origin. A ridge can occur as either an isolated, independent feature or part of a larger geomorphological and/or structural feature. Frequently, a ridge can be further subdivided into smaller geomorphic or structural elements.

कटक (ridge) ऐसी भूवैज्ञानिक स्थलाकृती होती है जिसमें धरती, बर्फ़ या किसी अन्य स्थाकृतिक सामग्री का एक उभरा हुआ और तंग अंश कुछ दूरी तक लगातार चले। उदाहरण के लिये पर्वतमालाओं के अक्सर पर्वतों के शिखरों पर लम्बी दूरी तक कटक की आकृति मिलती है, जो समभ्व है कि शिखरों के बीच ज़रा कम ऊँचाई की हो, लेकिन आसपास की धरती से स्पष्ट ऊँची प्रतीत होती है।