This question came up during an online book study I participated in, and then professional development session I lead. There is no easy answer for the question as reading encompasses multitude of behaviors.
Thinking about a toddler, it is when they flip through the pages of a favorite book and “read” the story from the pictures. For an early elementary grade student, it is when they use strategies to decode words to read what is on the page of text. For a striving reader, it is when they listen to a book read aloud and can tell you about it. A fluent reader not only decodes the words, but also creates meaning to develop an understanding of the text. With technology, reading is the ability to click on hot links to find out more information or to access video, sound recordings, or other media on the topic. Additionally, reading includes being able to discriminate what media is fact and what is fiction.
Fountas and Pinnell state there are 12 Systems of Strategic Actions readers utilize: searching for and using information, monitoring and self-correcting, solving words, maintaining fluency, adjusting, summarizing, predicting, making connections, synthesizing, inferring, analyzing, and critiquing (The Literacy Continuum, 2017). These are categorized into three different types of thinking: within, beyond, and about text. Thinking within text involves determining the author’s literal message, as well as strategies for decoding and fluency. Thinking beyond text requires making inferences, predicting, making connections, and synthesizing information. These strategies are commonly referred to as metacognition. In thinking about text, readers analyze and critique the author’s craft. All of these strategies help students with processing texts. They are not hierarchical and can occur in combination with each other. Readers need to employee a balance of strategic behaviors in order to be successful. They are what makes reading rocket science.
This rocket science cannot be learned by simply reading short passages of text to answer questions. Students need to be immersed in a variety of text and lots of it to develop into critical analyzers of print. It is akin to the baseball player who takes steps to improve their batting average by constantly hitting the ball. However, as we know, practice does not make perfect, rather perfect practice makes something perfect. The same baseball player does not just swing the bat, while hitting a coach is there explaining what went well and what adjustments need to be made. Likewise, this is true of teaching someone to read, they need to have time to read quality material as well as coaching on the use of reading strategic behaviors.
So, going back to the original question… reading is the ability to decipher text, in any medium, and use it to create understanding.