What is "machine learning"?

Machine learning is defined as a subset of artificial intelligence in which systems use algorithms to learn from data. This involves training models on large datasets, allowing the systems to identify patterns and make predictions or decisions based on new data inputs. The essence of machine learning lies in its ability to improve over time as it processes more information, thus enabling applications ranging from image recognition and natural language processing to recommendation systems and autonomous vehicles.

The other options describe concepts that are not accurately aligned with the definition of machine learning. Manual program coding represents traditional software development methods rather than the autonomous learning processes of machine learning. Complex hardware development typically pertains to engineering and computer architecture rather than learning from data. Lastly, enhancing internet connectivity relates to networking technologies, which do not directly involve learning algorithms in the manner that machine learning does.