Behind and By

Behind adverb - In or to or toward the rear.

By and behind are semantically related in beyond topic. In some cases you can use "By" instead a preposition "Behind", when it comes to topics like to, for.

By adverb - At, within, or to a short distance or time.

Behind and by are semantically related in beyond topic. Sometimes you can use "Behind" instead a preposition "By", if it concerns topics such as to, for.