Definition of Enter

To form a constituent part; to become a part or partaker; to impenetrate; share or mix with, as, tin “enters” into the composition of pewter. Bedford v. Colorado Fuel & Iron Corporation, 102 Colo. 538, 81 P.2d 752, 755. To go or come into a place or condition; to make or effect an entrance; to cause to go into or be received into. Hancock v. State, Tex.Cr. App., 363 S.W.2d 273, 275.

In the law of real property, to go upon land for the purpose of taking possession of it. In strict usage, the entering is preliminary to the taking possession but in common parlance the entry is now merged in the taking possession. See Entry.

To place anything before a court, or upon or among the records, in a formal and regular manner, and usually in writing; as to “enter an appearance,” to “enter a judgment.” In this sense the word is nearly equivalent to setting down formally in writing, in either a full or abridged form. See Appearance; Docket; Entering judgments; Entry.

That's the definition of Enter in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.