Key Difference: Lesson and Chapter in academic life like in school, both the words are used interchangeably like for example:

1. Open your books, we will study the next lesson.

2. Open your books, we will be studying the next chapter today.

But, be careful while using these words as both of them does not mean the same thing in day-to-day life. While for students, reading the next chapter becomes the sub-head in a textbook (physical or electronic) and a lesson becomes a topic under the sub-head or the broader chapter.

The key difference between both the words is Lesson in simple terms means teaching or learning a particular skill using a certain procedure, For example:

1. My experience taught that it is better to stay honest and true than to lie. (This is experience teaching a person a life lesson.)

2. Today in Science, we will do Anatomy and will cover Human Anatomy today. (This sentence explains that the teacher is teaching Science as a subject, with Chapter name as Anatomy in that the subsection topic or lesson as Human Anatomy.)

Whereas, Chapter is more or less like a division of a relative length or to signify milestone of a story or in life. For example:

1. I reached a new chapter in my life.

2. I am on the 4^th chapter.

Lesson

A lesson is a period, during which you learn lot of things about specific skill or about a certain topic. Lesson are generally step wise (phase) activities to progress or to achieve a certain goal or qualification like to learn driving by ​taking driving lessons or by attending specific number of lessons. The word lesson comes from Latin 'lectio', which means the 'action of reading (out)'. Since then the word was often used for the text itself, generally a passage from the Bible read out during a religious service. Thus, any portion of a book to be studied was referred to as a lesson. A lesson is a structured period of time where learning is intended to occur. Lesson is defined as 'a period of learning and teaching' by definition given by oxforddictionaries.com, while there are other definitions and meanings of lesson given at Dictionary.com like:

• a section into which a course is divided, especially a single continuous session of formal instruction on a subject.

• A part of a book or an exercise assigned to a student for study.

• Something to be learned.

Lesson involves one or more students being taught by a teacher or instructor. A lesson may either be one section of a textbook or a short period of time during which people (learners or pupils) are taught about a particular subject or an activity.  In other general and wider sense,a lesson is an insight gained by a learner into a previously unfamiliar topic. Lesson taught can be either planned like teaching or accidental like experience or painful if it means to teach a lesson to a person for mistake or to ensure that the person does not repeat something. Lessons can also be enjoyed by using entertaining mediums in teaching techniques by combining education and entertainment together from which the term 'Edutainmnet' was coined. There are various methods of teaching a lesson and this involves the latest edutainment lesson technique that has visual, virtual learning environment coupled with electronic learning.