Purpose
Goal, Motive
noun
When your eye is on the target you know your purpose. You also have your eye on the goal (that's the target, after all!).
もくてき
The reading is a reading for 目 that's abnormal. You've seen this reading with 目標 and 目次, though, so hopefully it won't be too hard at this point. Just imagine telling someone your 目的, only to have them laugh in your face and begin mocking もく you for it. Now you're not so sure if your goal is going to work.
一体、目的は何なんですか?
What the heck is your goal?
着付けが出来るようになるのが目的で、この料ていで働き始めました。
I started working at this fancy Japanese-style restaurant with my motive being the ability to wear kimono.
私たちの目的は、一緒に楽しみながら皆さんに日本語を勉強してもらうことです。
Our goal is to make you all have fun while studying Japanese together.