An objective is a description of performance you want learners to be able to exhibit before you consider them competent. An objective describes an intended result of instruction, rather than the process of instruction itself.
Explicit objectives are important for a number of reasons.
First, when clearly defined objectives are lacking, there is no sound basis for the selection or designing of instructional materials, content, or methods. If you don't know where you're going, it is difficult to select a suitable means for getting there. Instructors simply function in a fog of their own making unless they know what they want their students to accomplish as a result of their instruction. A second important reason for stating objectives sharply has to do with finding out whether the objective has, in fact, been accomplished. Test or examinations are the mileposts along the road of learning and are supposed to tell instructors and students alike whether they have been successful in achieving the course objectives.