Plain English Meaning

It is the middle part of a lesson — after the introduction and before the conclusion — where the actual teaching happens, with each point building on the one before it.

Full Definition

In lesson planning, development is the main body of a lesson, where new material is presented, explained, and built up step by step from what the student already knows toward the new knowledge or skill being taught.

Context Anchor

Seen in flight instructor lesson plans and in the Aviation Instructor’s Handbook discussion of organizing teaching material.

Derivation

From the Latin 'dis-' (apart) and 'voloper' (to wrap), through Old French — literally 'to unwrap' or 'unfold.' In teaching, the lesson is unfolded for the student, one layer at a time.