Ponds and lakes are very similar. Both are small bodies of water, either natural or man-made, that are completely surrounded by land. The primary difference between the two is their size. Simply put, lakes are larger and ponds are smaller. However, there is no standardization of lake sizes. Some sources claim lakes are bodies of water larger than 2 acres. In Montana, the minimum water surface area of a lake is 20 acres. But since the size of your body of water isn't a clear indicator, here are a few more factors to consider:
Generally, a lake is an area of open, relatively deep water that is large enough to produce a wave-swept "washed" shoreline, which can prevent vegetation from growing along the shore.
Another difference can be seen in the water's temperature. Lakes, because they are deeper, have a stratified temperature structure that depends on the season. During summer months three distinct layers develop: The top layer stays warm at around 65-75 degrees. The middle layer drops dramatically, usually to 45-65 degrees F. The bottom layer is the coldest, staying at around 39-45 degrees F. Ponds, on the other hand, have a more consistent temperature throughout.
If the water is deep enough that light does not penetrate to the bottom, and photosynthesis is limited to the top layer, the body of water is considered a lake.
A pond is a body of water shallow enough to support rooted plants. Many times plants grow all the way across a shallow pond. There is little wave action and the bottom is usually covered with mud. Plants can, and often do, grow along a pond's edge.
Even in cold climates, most lakes are large enough so that they don't freeze solid, unlike ponds.
Finally, if the lake is large enough, it can affect the surrounding climate, whereas ponds are usually affected by the surrounding climate.
Based on the depth of your body of water-congratulations! It's a lake. And, if you're looking to give your water body a name, we, the editors at Infoplease.com, grant you full permission to name it after us!