An investment is an asset or item that is purchased with the hope that it will generate income or appreciate in value at some point in the future.
An investment always concerns putting away some asset today (time, money, effort, etc.) in hopes of a greater value in the future than what was originally put in.
You can relax because, your initial deposit is always secure and when the investment cycle is completed, there is going to be value more than what you invested waiting for you.